Merge pull request #20878 from tiehuis/std-math-complex-fixes

std.math.complex fixes

19 files changed, 102 insertions, 120 deletions

diff --git a/lib/std/math/complex/abs.zig b/lib/std/math/complex/abs.zig
index ab85f2c36c..8b75db4a61 100644
--- a/lib/std/math/complex/abs.zig
+++ b/lib/std/math/complex/abs.zig
@@ -9,10 +9,9 @@ pub fn abs(z: anytype) @TypeOf(z.re, z.im) {
     return math.hypot(z.re, z.im);
 }
 
-const epsilon = 0.0001;
-
 test abs {
+    const epsilon = math.floatEps(f32);
     const a = Complex(f32).init(5, 3);
     const c = abs(a);
-    try testing.expect(math.approxEqAbs(f32, c, 5.83095, epsilon));
+    try testing.expectApproxEqAbs(5.8309517, c, epsilon);
 }
diff --git a/lib/std/math/complex/acos.zig b/lib/std/math/complex/acos.zig
index 9cbfaffe4b..afaae740d9 100644
--- a/lib/std/math/complex/acos.zig
+++ b/lib/std/math/complex/acos.zig
@@ -11,12 +11,11 @@ pub fn acos(z: anytype) Complex(@TypeOf(z.re, z.im)) {
     return Complex(T).init(@as(T, math.pi) / 2 - q.re, -q.im);
 }
 
-const epsilon = 0.0001;
-
 test acos {
+    const epsilon = math.floatEps(f32);
     const a = Complex(f32).init(5, 3);
     const c = acos(a);
 
-    try testing.expect(math.approxEqAbs(f32, c.re, 0.546975, epsilon));
-    try testing.expect(math.approxEqAbs(f32, c.im, -2.452914, epsilon));
+    try testing.expectApproxEqAbs(0.5469737, c.re, epsilon);
+    try testing.expectApproxEqAbs(-2.4529128, c.im, epsilon);
 }
diff --git a/lib/std/math/complex/acosh.zig b/lib/std/math/complex/acosh.zig
index dba8b03794..dbb7104343 100644
--- a/lib/std/math/complex/acosh.zig
+++ b/lib/std/math/complex/acosh.zig
@@ -8,15 +8,18 @@ const Complex = cmath.Complex;
 pub fn acosh(z: anytype) Complex(@TypeOf(z.re, z.im)) {
     const T = @TypeOf(z.re, z.im);
     const q = cmath.acos(z);
-    return Complex(T).init(-q.im, q.re);
-}
 
-const epsilon = 0.0001;
+    return if (math.signbit(z.im))
+        Complex(T).init(q.im, -q.re)
+    else
+        Complex(T).init(-q.im, q.re);
+}
 
 test acosh {
+    const epsilon = math.floatEps(f32);
     const a = Complex(f32).init(5, 3);
     const c = acosh(a);
 
-    try testing.expect(math.approxEqAbs(f32, c.re, 2.452914, epsilon));
-    try testing.expect(math.approxEqAbs(f32, c.im, 0.546975, epsilon));
+    try testing.expectApproxEqAbs(2.4529128, c.re, epsilon);
+    try testing.expectApproxEqAbs(0.5469737, c.im, epsilon);
 }
diff --git a/lib/std/math/complex/arg.zig b/lib/std/math/complex/arg.zig
index ac69276d96..12986c7c8d 100644
--- a/lib/std/math/complex/arg.zig
+++ b/lib/std/math/complex/arg.zig
@@ -9,10 +9,9 @@ pub fn arg(z: anytype) @TypeOf(z.re, z.im) {
     return math.atan2(z.im, z.re);
 }
 
-const epsilon = 0.0001;
-
 test arg {
+    const epsilon = math.floatEps(f32);
     const a = Complex(f32).init(5, 3);
     const c = arg(a);
-    try testing.expect(math.approxEqAbs(f32, c, 0.540420, epsilon));
+    try testing.expectApproxEqAbs(0.5404195, c, epsilon);
 }
diff --git a/lib/std/math/complex/asin.zig b/lib/std/math/complex/asin.zig
index deacfa26ea..bf3e9a00da 100644
--- a/lib/std/math/complex/asin.zig
+++ b/lib/std/math/complex/asin.zig
@@ -17,12 +17,11 @@ pub fn asin(z: anytype) Complex(@TypeOf(z.re, z.im)) {
     return Complex(T).init(r.im, -r.re);
 }
 
-const epsilon = 0.0001;
-
 test asin {
+    const epsilon = math.floatEps(f32);
     const a = Complex(f32).init(5, 3);
     const c = asin(a);
 
-    try testing.expect(math.approxEqAbs(f32, c.re, 1.023822, epsilon));
-    try testing.expect(math.approxEqAbs(f32, c.im, 2.452914, epsilon));
+    try testing.expectApproxEqAbs(1.0238227, c.re, epsilon);
+    try testing.expectApproxEqAbs(2.4529128, c.im, epsilon);
 }
diff --git a/lib/std/math/complex/asinh.zig b/lib/std/math/complex/asinh.zig
index 2dcfc9c2ac..4923caff50 100644
--- a/lib/std/math/complex/asinh.zig
+++ b/lib/std/math/complex/asinh.zig
@@ -12,12 +12,11 @@ pub fn asinh(z: anytype) Complex(@TypeOf(z.re, z.im)) {
     return Complex(T).init(r.im, -r.re);
 }
 
-const epsilon = 0.0001;
-
 test asinh {
+    const epsilon = math.floatEps(f32);
     const a = Complex(f32).init(5, 3);
     const c = asinh(a);
 
-    try testing.expect(math.approxEqAbs(f32, c.re, 2.459831, epsilon));
-    try testing.expect(math.approxEqAbs(f32, c.im, 0.533999, epsilon));
+    try testing.expectApproxEqAbs(2.4598298, c.re, epsilon);
+    try testing.expectApproxEqAbs(0.5339993, c.im, epsilon);
 }
diff --git a/lib/std/math/complex/atan.zig b/lib/std/math/complex/atan.zig
index 33109178f8..9e9e94622c 100644
--- a/lib/std/math/complex/atan.zig
+++ b/lib/std/math/complex/atan.zig
@@ -32,37 +32,22 @@ fn redupif32(x: f32) f32 {
         t -= 0.5;
     }
 
-    const u = @as(f32, @floatFromInt(@as(i32, @intFromFloat(t))));
-    return ((x - u * DP1) - u * DP2) - t * DP3;
+    const u: f32 = @trunc(t);
+    return ((x - u * DP1) - u * DP2) - u * DP3;
 }
 
 fn atan32(z: Complex(f32)) Complex(f32) {
-    const maxnum = 1.0e38;
-
     const x = z.re;
     const y = z.im;
 
-    if ((x == 0.0) and (y > 1.0)) {
-        // overflow
-        return Complex(f32).init(maxnum, maxnum);
-    }
-
     const x2 = x * x;
     var a = 1.0 - x2 - (y * y);
-    if (a == 0.0) {
-        // overflow
-        return Complex(f32).init(maxnum, maxnum);
-    }
 
     var t = 0.5 * math.atan2(2.0 * x, a);
     const w = redupif32(t);
 
     t = y - 1.0;
     a = x2 + t * t;
-    if (a == 0.0) {
-        // overflow
-        return Complex(f32).init(maxnum, maxnum);
-    }
 
     t = y + 1.0;
     a = (x2 + (t * t)) / a;
@@ -81,57 +66,42 @@ fn redupif64(x: f64) f64 {
         t -= 0.5;
     }
 
-    const u = @as(f64, @floatFromInt(@as(i64, @intFromFloat(t))));
-    return ((x - u * DP1) - u * DP2) - t * DP3;
+    const u: f64 = @trunc(t);
+    return ((x - u * DP1) - u * DP2) - u * DP3;
 }
 
 fn atan64(z: Complex(f64)) Complex(f64) {
-    const maxnum = 1.0e308;
-
     const x = z.re;
     const y = z.im;
 
-    if ((x == 0.0) and (y > 1.0)) {
-        // overflow
-        return Complex(f64).init(maxnum, maxnum);
-    }
-
     const x2 = x * x;
     var a = 1.0 - x2 - (y * y);
-    if (a == 0.0) {
-        // overflow
-        return Complex(f64).init(maxnum, maxnum);
-    }
 
     var t = 0.5 * math.atan2(2.0 * x, a);
     const w = redupif64(t);
 
     t = y - 1.0;
     a = x2 + t * t;
-    if (a == 0.0) {
-        // overflow
-        return Complex(f64).init(maxnum, maxnum);
-    }
 
     t = y + 1.0;
     a = (x2 + (t * t)) / a;
     return Complex(f64).init(w, 0.25 * @log(a));
 }
 
-const epsilon = 0.0001;
-
 test atan32 {
+    const epsilon = math.floatEps(f32);
     const a = Complex(f32).init(5, 3);
     const c = atan(a);
 
-    try testing.expect(math.approxEqAbs(f32, c.re, 1.423679, epsilon));
-    try testing.expect(math.approxEqAbs(f32, c.im, 0.086569, epsilon));
+    try testing.expectApproxEqAbs(1.423679, c.re, epsilon);
+    try testing.expectApproxEqAbs(0.086569, c.im, epsilon);
 }
 
 test atan64 {
+    const epsilon = math.floatEps(f64);
     const a = Complex(f64).init(5, 3);
     const c = atan(a);
 
-    try testing.expect(math.approxEqAbs(f64, c.re, 1.423679, epsilon));
-    try testing.expect(math.approxEqAbs(f64, c.im, 0.086569, epsilon));
+    try testing.expectApproxEqAbs(1.4236790442393028, c.re, epsilon);
+    try testing.expectApproxEqAbs(0.08656905917945844, c.im, epsilon);
 }
diff --git a/lib/std/math/complex/atanh.zig b/lib/std/math/complex/atanh.zig
index 54d21fc433..86d5b3df23 100644
--- a/lib/std/math/complex/atanh.zig
+++ b/lib/std/math/complex/atanh.zig
@@ -12,12 +12,11 @@ pub fn atanh(z: anytype) Complex(@TypeOf(z.re, z.im)) {
     return Complex(T).init(r.im, -r.re);
 }
 
-const epsilon = 0.0001;
-
 test atanh {
+    const epsilon = math.floatEps(f32);
     const a = Complex(f32).init(5, 3);
     const c = atanh(a);
 
-    try testing.expect(math.approxEqAbs(f32, c.re, 0.146947, epsilon));
-    try testing.expect(math.approxEqAbs(f32, c.im, 1.480870, epsilon));
+    try testing.expectApproxEqAbs(0.14694665, c.re, epsilon);
+    try testing.expectApproxEqAbs(1.4808695, c.im, epsilon);
 }
diff --git a/lib/std/math/complex/conj.zig b/lib/std/math/complex/conj.zig
index b5a4d063d3..4a271c9801 100644
--- a/lib/std/math/complex/conj.zig
+++ b/lib/std/math/complex/conj.zig
@@ -14,5 +14,6 @@ test conj {
     const a = Complex(f32).init(5, 3);
     const c = a.conjugate();
 
-    try testing.expect(c.re == 5 and c.im == -3);
+    try testing.expectEqual(5, c.re);
+    try testing.expectEqual(-3, c.im);
 }
diff --git a/lib/std/math/complex/cos.zig b/lib/std/math/complex/cos.zig
index 389dd013e3..fee1a8c37a 100644
--- a/lib/std/math/complex/cos.zig
+++ b/lib/std/math/complex/cos.zig
@@ -11,12 +11,11 @@ pub fn cos(z: anytype) Complex(@TypeOf(z.re, z.im)) {
     return cmath.cosh(p);
 }
 
-const epsilon = 0.0001;
-
 test cos {
+    const epsilon = math.floatEps(f32);
     const a = Complex(f32).init(5, 3);
     const c = cos(a);
 
-    try testing.expect(math.approxEqAbs(f32, c.re, 2.855815, epsilon));
-    try testing.expect(math.approxEqAbs(f32, c.im, 9.606383, epsilon));
+    try testing.expectApproxEqAbs(2.8558152, c.re, epsilon);
+    try testing.expectApproxEqAbs(9.606383, c.im, epsilon);
 }
diff --git a/lib/std/math/complex/cosh.zig b/lib/std/math/complex/cosh.zig
index 42f5b432ec..d41b3fb06a 100644
--- a/lib/std/math/complex/cosh.zig
+++ b/lib/std/math/complex/cosh.zig
@@ -34,7 +34,7 @@ fn cosh32(z: Complex(f32)) Complex(f32) {
 
     if (ix < 0x7f800000 and iy < 0x7f800000) {
         if (iy == 0) {
-            return Complex(f32).init(math.cosh(x), y);
+            return Complex(f32).init(math.cosh(x), x * y);
         }
         // small x: normal case
         if (ix < 0x41100000) {
@@ -45,7 +45,7 @@ fn cosh32(z: Complex(f32)) Complex(f32) {
         if (ix < 0x42b17218) {
             // x < 88.7: exp(|x|) won't overflow
             const h = @exp(@abs(x)) * 0.5;
-            return Complex(f32).init(math.copysign(h, x) * @cos(y), h * @sin(y));
+            return Complex(f32).init(h * @cos(y), math.copysign(h, x) * @sin(y));
         }
         // x < 192.7: scale to avoid overflow
         else if (ix < 0x4340b1e7) {
@@ -68,7 +68,7 @@ fn cosh32(z: Complex(f32)) Complex(f32) {
         if (hx & 0x7fffff == 0) {
             return Complex(f32).init(x * x, math.copysign(@as(f32, 0.0), x) * y);
         }
-        return Complex(f32).init(x, math.copysign(@as(f32, 0.0), (x + x) * y));
+        return Complex(f32).init(x * x, math.copysign(@as(f32, 0.0), (x + x) * y));
     }
 
     if (ix < 0x7f800000 and iy >= 0x7f800000) {
@@ -123,7 +123,7 @@ fn cosh64(z: Complex(f64)) Complex(f64) {
         }
         // x >= 1455: result always overflows
         else {
-            const h = 0x1p1023;
+            const h = 0x1p1023 * x;
             return Complex(f64).init(h * h * @cos(y), h * @sin(y));
         }
     }
@@ -153,20 +153,29 @@ fn cosh64(z: Complex(f64)) Complex(f64) {
     return Complex(f64).init((x * x) * (y - y), (x + x) * (y - y));
 }
 
-const epsilon = 0.0001;
-
 test cosh32 {
+    const epsilon = math.floatEps(f32);
     const a = Complex(f32).init(5, 3);
     const c = cosh(a);
 
-    try testing.expect(math.approxEqAbs(f32, c.re, -73.467300, epsilon));
-    try testing.expect(math.approxEqAbs(f32, c.im, 10.471557, epsilon));
+    try testing.expectApproxEqAbs(-73.467300, c.re, epsilon);
+    try testing.expectApproxEqAbs(10.471557, c.im, epsilon);
 }
 
 test cosh64 {
+    const epsilon = math.floatEps(f64);
     const a = Complex(f64).init(5, 3);
     const c = cosh(a);
 
-    try testing.expect(math.approxEqAbs(f64, c.re, -73.467300, epsilon));
-    try testing.expect(math.approxEqAbs(f64, c.im, 10.471557, epsilon));
+    try testing.expectApproxEqAbs(-73.46729221264526, c.re, epsilon);
+    try testing.expectApproxEqAbs(10.471557674805572, c.im, epsilon);
+}
+
+test "cosh64 musl" {
+    const epsilon = math.floatEps(f64);
+    const a = Complex(f64).init(7.44648873421389e17, 1.6008058402057622e19);
+    const c = cosh(a);
+
+    try testing.expectApproxEqAbs(std.math.inf(f64), c.re, epsilon);
+    try testing.expectApproxEqAbs(std.math.inf(f64), c.im, epsilon);
 }
diff --git a/lib/std/math/complex/log.zig b/lib/std/math/complex/log.zig
index 65859c2dce..39174431f1 100644
--- a/lib/std/math/complex/log.zig
+++ b/lib/std/math/complex/log.zig
@@ -13,12 +13,11 @@ pub fn log(z: anytype) Complex(@TypeOf(z.re, z.im)) {
     return Complex(T).init(@log(r), phi);
 }
 
-const epsilon = 0.0001;
-
 test log {
+    const epsilon = math.floatEps(f32);
     const a = Complex(f32).init(5, 3);
     const c = log(a);
 
-    try testing.expect(math.approxEqAbs(f32, c.re, 1.763180, epsilon));
-    try testing.expect(math.approxEqAbs(f32, c.im, 0.540419, epsilon));
+    try testing.expectApproxEqAbs(1.7631803, c.re, epsilon);
+    try testing.expectApproxEqAbs(0.5404195, c.im, epsilon);
 }
diff --git a/lib/std/math/complex/pow.zig b/lib/std/math/complex/pow.zig
index 874e4037dc..6fcca6b864 100644
--- a/lib/std/math/complex/pow.zig
+++ b/lib/std/math/complex/pow.zig
@@ -9,13 +9,12 @@ pub fn pow(z: anytype, s: anytype) Complex(@TypeOf(z.re, z.im, s.re, s.im)) {
     return cmath.exp(cmath.log(z).mul(s));
 }
 
-const epsilon = 0.0001;
-
 test pow {
+    const epsilon = math.floatEps(f32);
     const a = Complex(f32).init(5, 3);
     const b = Complex(f32).init(2.3, -1.3);
     const c = pow(a, b);
 
-    try testing.expect(math.approxEqAbs(f32, c.re, 58.049110, epsilon));
-    try testing.expect(math.approxEqAbs(f32, c.im, -101.003433, epsilon));
+    try testing.expectApproxEqAbs(58.049110, c.re, epsilon);
+    try testing.expectApproxEqAbs(-101.003433, c.im, epsilon);
 }
diff --git a/lib/std/math/complex/proj.zig b/lib/std/math/complex/proj.zig
index b7d3d58b12..243e5133c3 100644
--- a/lib/std/math/complex/proj.zig
+++ b/lib/std/math/complex/proj.zig
@@ -19,5 +19,6 @@ test proj {
     const a = Complex(f32).init(5, 3);
     const c = proj(a);
 
-    try testing.expect(c.re == 5 and c.im == 3);
+    try testing.expectEqual(5, c.re);
+    try testing.expectEqual(3, c.im);
 }
diff --git a/lib/std/math/complex/sin.zig b/lib/std/math/complex/sin.zig
index 3ca2419e43..5ce5b335f8 100644
--- a/lib/std/math/complex/sin.zig
+++ b/lib/std/math/complex/sin.zig
@@ -12,12 +12,11 @@ pub fn sin(z: anytype) Complex(@TypeOf(z.re, z.im)) {
     return Complex(T).init(q.im, -q.re);
 }
 
-const epsilon = 0.0001;
-
 test sin {
+    const epsilon = math.floatEps(f32);
     const a = Complex(f32).init(5, 3);
     const c = sin(a);
 
-    try testing.expect(math.approxEqAbs(f32, c.re, -9.654126, epsilon));
-    try testing.expect(math.approxEqAbs(f32, c.im, 2.841692, epsilon));
+    try testing.expectApproxEqAbs(-9.654126, c.re, epsilon);
+    try testing.expectApproxEqAbs(2.8416924, c.im, epsilon);
 }
diff --git a/lib/std/math/complex/sinh.zig b/lib/std/math/complex/sinh.zig
index 911587a9c5..ae8fadb9ab 100644
--- a/lib/std/math/complex/sinh.zig
+++ b/lib/std/math/complex/sinh.zig
@@ -152,20 +152,20 @@ fn sinh64(z: Complex(f64)) Complex(f64) {
     return Complex(f64).init((x * x) * (y - y), (x + x) * (y - y));
 }
 
-const epsilon = 0.0001;
-
 test sinh32 {
+    const epsilon = math.floatEps(f32);
     const a = Complex(f32).init(5, 3);
     const c = sinh(a);
 
-    try testing.expect(math.approxEqAbs(f32, c.re, -73.460617, epsilon));
-    try testing.expect(math.approxEqAbs(f32, c.im, 10.472508, epsilon));
+    try testing.expectApproxEqAbs(-73.460617, c.re, epsilon);
+    try testing.expectApproxEqAbs(10.472508, c.im, epsilon);
 }
 
 test sinh64 {
+    const epsilon = math.floatEps(f64);
     const a = Complex(f64).init(5, 3);
     const c = sinh(a);
 
-    try testing.expect(math.approxEqAbs(f64, c.re, -73.460617, epsilon));
-    try testing.expect(math.approxEqAbs(f64, c.im, 10.472508, epsilon));
+    try testing.expectApproxEqAbs(-73.46062169567367, c.re, epsilon);
+    try testing.expectApproxEqAbs(10.472508533940392, c.im, epsilon);
 }
diff --git a/lib/std/math/complex/sqrt.zig b/lib/std/math/complex/sqrt.zig
index 0edf18fb23..f8f7798ae9 100644
--- a/lib/std/math/complex/sqrt.zig
+++ b/lib/std/math/complex/sqrt.zig
@@ -43,7 +43,7 @@ fn sqrt32(z: Complex(f32)) Complex(f32) {
         // sqrt(-inf + i nan)   = nan +- inf i
         // sqrt(-inf + iy)      = 0 + inf i
         if (math.signbit(x)) {
-            return Complex(f32).init(@abs(x - y), math.copysign(x, y));
+            return Complex(f32).init(@abs(y - y), math.copysign(x, y));
         } else {
             return Complex(f32).init(x, math.copysign(y - y, y));
         }
@@ -94,7 +94,7 @@ fn sqrt64(z: Complex(f64)) Complex(f64) {
         // sqrt(-inf + i nan)   = nan +- inf i
         // sqrt(-inf + iy)      = 0 + inf i
         if (math.signbit(x)) {
-            return Complex(f64).init(@abs(x - y), math.copysign(x, y));
+            return Complex(f64).init(@abs(y - y), math.copysign(x, y));
         } else {
             return Complex(f64).init(x, math.copysign(y - y, y));
         }
@@ -127,20 +127,20 @@ fn sqrt64(z: Complex(f64)) Complex(f64) {
     return result;
 }
 
-const epsilon = 0.0001;
-
 test sqrt32 {
+    const epsilon = math.floatEps(f32);
     const a = Complex(f32).init(5, 3);
     const c = sqrt(a);
 
-    try testing.expect(math.approxEqAbs(f32, c.re, 2.327117, epsilon));
-    try testing.expect(math.approxEqAbs(f32, c.im, 0.644574, epsilon));
+    try testing.expectApproxEqAbs(2.3271174, c.re, epsilon);
+    try testing.expectApproxEqAbs(0.6445742, c.im, epsilon);
 }
 
 test sqrt64 {
+    const epsilon = math.floatEps(f64);
     const a = Complex(f64).init(5, 3);
     const c = sqrt(a);
 
-    try testing.expect(math.approxEqAbs(f64, c.re, 2.3271175190399496, epsilon));
-    try testing.expect(math.approxEqAbs(f64, c.im, 0.6445742373246469, epsilon));
+    try testing.expectApproxEqAbs(2.3271175190399496, c.re, epsilon);
+    try testing.expectApproxEqAbs(0.6445742373246469, c.im, epsilon);
 }
diff --git a/lib/std/math/complex/tan.zig b/lib/std/math/complex/tan.zig
index ad5b1b47b6..4c3629046a 100644
--- a/lib/std/math/complex/tan.zig
+++ b/lib/std/math/complex/tan.zig
@@ -12,12 +12,11 @@ pub fn tan(z: anytype) Complex(@TypeOf(z.re, z.im)) {
     return Complex(T).init(r.im, -r.re);
 }
 
-const epsilon = 0.0001;
-
 test tan {
+    const epsilon = math.floatEps(f32);
     const a = Complex(f32).init(5, 3);
     const c = tan(a);
 
-    try testing.expect(math.approxEqAbs(f32, c.re, -0.002708233, epsilon));
-    try testing.expect(math.approxEqAbs(f32, c.im, 1.004165, epsilon));
+    try testing.expectApproxEqAbs(-0.002708233, c.re, epsilon);
+    try testing.expectApproxEqAbs(1.0041647, c.im, epsilon);
 }
diff --git a/lib/std/math/complex/tanh.zig b/lib/std/math/complex/tanh.zig
index 8a1d46eca7..af2ed4f061 100644
--- a/lib/std/math/complex/tanh.zig
+++ b/lib/std/math/complex/tanh.zig
@@ -70,7 +70,7 @@ fn tanh64(z: Complex(f64)) Complex(f64) {
     const ix = hx & 0x7fffffff;
 
     if (ix >= 0x7ff00000) {
-        if ((ix & 0x7fffff) | lx != 0) {
+        if ((ix & 0xfffff) | lx != 0) {
             const r = if (y == 0) y else x * y;
             return Complex(f64).init(x, r);
         }
@@ -101,20 +101,29 @@ fn tanh64(z: Complex(f64)) Complex(f64) {
     return Complex(f64).init((beta * rho * s) / den, t / den);
 }
 
-const epsilon = 0.0001;
-
 test tanh32 {
+    const epsilon = math.floatEps(f32);
     const a = Complex(f32).init(5, 3);
     const c = tanh(a);
 
-    try testing.expect(math.approxEqAbs(f32, c.re, 0.999913, epsilon));
-    try testing.expect(math.approxEqAbs(f32, c.im, -0.000025, epsilon));
+    try testing.expectApproxEqAbs(0.99991274, c.re, epsilon);
+    try testing.expectApproxEqAbs(-0.00002536878, c.im, epsilon);
 }
 
 test tanh64 {
+    const epsilon = math.floatEps(f64);
     const a = Complex(f64).init(5, 3);
     const c = tanh(a);
 
-    try testing.expect(math.approxEqAbs(f64, c.re, 0.999913, epsilon));
-    try testing.expect(math.approxEqAbs(f64, c.im, -0.000025, epsilon));
+    try testing.expectApproxEqAbs(0.9999128201513536, c.re, epsilon);
+    try testing.expectApproxEqAbs(-0.00002536867620767604, c.im, epsilon);
+}
+
+test "tanh64 musl" {
+    const epsilon = math.floatEps(f64);
+    const a = Complex(f64).init(std.math.inf(f64), std.math.inf(f64));
+    const c = tanh(a);
+
+    try testing.expectApproxEqAbs(1, c.re, epsilon);
+    try testing.expectApproxEqAbs(0, c.im, epsilon);
 }