Commit 62323eeb75
Changed files (4)
std
special
std/math/exp.zig
@@ -11,7 +11,7 @@ pub fn exp(x: var) -> @typeOf(x) {
}
fn exp32(x_: f32) -> f32 {
- const half = []const f32 { 0.5, -0.5 };
+ const half = []f32 { 0.5, -0.5 };
const ln2hi = 6.9314575195e-1;
const ln2lo = 1.4286067653e-6;
const invln2 = 1.4426950216e+0;
std/math/ln.zig
@@ -120,12 +120,12 @@ fn lnd(x_: f64) -> f64 {
s * (hfsq + R) + dk * ln2_lo - hfsq + f + dk * ln2_hi
}
-test "log" {
+test "math.ln" {
assert(ln(f32(0.2)) == lnf(0.2));
assert(ln(f64(0.2)) == lnd(0.2));
}
-test "logf" {
+test "math.ln32" {
const epsilon = 0.000001;
assert(math.approxEq(f32, lnf(0.2), -1.609438, epsilon));
@@ -136,7 +136,7 @@ test "logf" {
assert(math.approxEq(f32, lnf(123123.234375), 11.720941, epsilon));
}
-test "logd" {
+test "math.ln64" {
const epsilon = 0.000001;
assert(math.approxEq(f64, lnd(0.2), -1.609438, epsilon));
std/math/pow.zig
@@ -1,21 +1,12 @@
const math = @import("index.zig");
const assert = @import("../debug.zig").assert;
+// This implementation is taken from the go stlib, musl is a bit more complex.
pub fn pow(comptime T: type, x: T, y: T) -> T {
- switch (T) {
- f32 => @inlineCall(pow32, x, y),
- f64 => @inlineCall(pow64, x, y),
- else => @compileError("pow not implemented for " ++ @typeName(T)),
+ if (T != f32 and T != f64) {
+ @compileError("pow not implemented for " ++ @typeName(T));
}
-}
-fn isOddInteger(x: f64) -> bool {
- const r = math.modf(x);
- r.fpart == 0.0 and i64(r.ipart) & 1 == 1
-}
-
-// This implementation is taken from the go stlib, musl is a bit more complex.
-fn pow32(x: f32, y: f32) -> f32 {
// pow(x, +-0) = 1 for all x
// pow(1, y) = 1 for all y
if (y == 0 or x == 1) {
@@ -25,7 +16,7 @@ fn pow32(x: f32, y: f32) -> f32 {
// pow(nan, y) = nan for all y
// pow(x, nan) = nan for all x
if (math.isNan(x) or math.isNan(y)) {
- return math.nan(f32);
+ return math.nan(T);
}
// pow(x, 1) = x for all x
@@ -46,11 +37,11 @@ fn pow32(x: f32, y: f32) -> f32 {
if (y < 0) {
// pow(+-0, y) = +- 0 for y an odd integer
if (isOddInteger(y)) {
- return math.copysign(f32, math.inf(f32), x);
+ return math.copysign(T, math.inf(T), x);
}
// pow(+-0, y) = +inf for y an even integer
else {
- return math.inf(f32);
+ return math.inf(T);
}
} else {
if (isOddInteger(y)) {
@@ -74,13 +65,13 @@ fn pow32(x: f32, y: f32) -> f32 {
// pow(x, -inf) = +inf for |x| < 1
// pow(x, +inf) = +inf for |x| > 1
else {
- return math.inf(f32);
+ return math.inf(T);
}
}
if (math.isInf(x)) {
if (math.isNegativeInf(x)) {
- return pow32(1 / x, -y);
+ return pow(T, 1 / x, -y);
}
// pow(+inf, y) = +0 for y < 0
else if (y < 0) {
@@ -88,7 +79,7 @@ fn pow32(x: f32, y: f32) -> f32 {
}
// pow(+inf, y) = +0 for y > 0
else if (y > 0) {
- return math.inf(f32);
+ return math.inf(T);
}
}
@@ -104,14 +95,14 @@ fn pow32(x: f32, y: f32) -> f32 {
var yf = r1.fpart;
if (yf != 0 and x < 0) {
- return math.nan(f32);
+ return math.nan(T);
}
- if (yi >= 1 << 31) {
+ if (yi >= 1 << (T.bit_count - 1)) {
return math.exp(y * math.ln(x));
}
// a = a1 * 2^ae
- var a1: f32 = 1.0;
+ var a1: T = 1.0;
var ae: i32 = 0;
// a *= x^yf
@@ -151,166 +142,26 @@ fn pow32(x: f32, y: f32) -> f32 {
math.scalbn(a1, ae)
}
-// This implementation is taken from the go stlib, musl is a bit more complex.
-fn pow64(x: f64, y: f64) -> f64 {
- // pow(x, +-0) = 1 for all x
- // pow(1, y) = 1 for all y
- if (y == 0 or x == 1) {
- return 1;
- }
-
- // pow(nan, y) = nan for all y
- // pow(x, nan) = nan for all x
- if (math.isNan(x) or math.isNan(y)) {
- return math.nan(f64);
- }
-
- // pow(x, 1) = x for all x
- if (y == 1) {
- return x;
- }
-
- // special case sqrt
- if (y == 0.5) {
- return math.sqrt(x);
- }
-
- if (y == -0.5) {
- return 1 / math.sqrt(x);
- }
-
- if (x == 0) {
- if (y < 0) {
- // pow(+-0, y) = +- 0 for y an odd integer
- if (isOddInteger(y)) {
- return math.copysign(f64, math.inf(f64), x);
- }
- // pow(+-0, y) = +inf for y an even integer
- else {
- return math.inf(f64);
- }
- } else {
- if (isOddInteger(y)) {
- return x;
- } else {
- return 0;
- }
- }
- }
-
- if (math.isInf(y)) {
- // pow(-1, inf) = -1 for all x
- if (x == -1) {
- return -1;
- }
- // pow(x, +inf) = +0 for |x| < 1
- // pow(x, -inf) = +0 for |x| > 1
- else if ((math.fabs(x) < 1) == math.isInf(y)) {
- return 0;
- }
- // pow(x, -inf) = +inf for |x| < 1
- // pow(x, +inf) = +inf for |x| > 1
- else {
- return math.inf(f64);
- }
- }
-
- if (math.isInf(x)) {
- if (math.isInf(x)) {
- return pow64(1 / x, -y);
- }
- // pow(+inf, y) = +0 for y < 0
- else if (y < 0) {
- return 0;
- }
- // pow(+inf, y) = +0 for y > 0
- else if (y > 0) {
- return math.inf(f64);
- }
- }
-
- var ay = y;
- var flip = false;
- if (ay < 0) {
- ay = -ay;
- flip = true;
- }
-
- const r1 = math.modf(ay);
- var yi = r1.ipart;
- var yf = r1.fpart;
-
- if (yf != 0 and x < 0) {
- return math.nan(f64);
- }
- if (yi >= 1 << 63) {
- return math.exp(y * math.ln(x));
- }
-
- // a = a1 * 2^ae
- var a1: f64 = 1.0;
- var ae: i32 = 0;
-
- // a *= x^yf
- if (yf != 0) {
- if (yf > 0.5) {
- yf -= 1;
- yi += 1;
- }
- a1 = math.exp(yf * math.ln(x));
- }
-
- // a *= x^yi
- const r2 = math.frexp(x);
- var xe = r2.exponent;
- var x1 = r2.significand;
-
- var i = i64(yi);
- while (i != 0) : (i >>= 1) {
- if (i & 1 == 1) {
- a1 *= x1;
- ae += xe;
- }
- x1 *= x1;
- xe <<= 1;
- if (x1 < 0.5) {
- x1 += x1;
- xe -= 1;
- }
- }
-
- // a *= a1 * 2^ae
- if (flip) {
- a1 = 1 / a1;
- ae = -ae;
- }
-
- math.scalbn(a1, ae)
-}
-
-test "pow" {
- assert(pow(f32, 0.2, 3.3) == pow32(0.2, 3.3));
- assert(pow(f64, 0.2, 3.3) == pow64(0.2, 3.3));
+fn isOddInteger(x: f64) -> bool {
+ const r = math.modf(x);
+ r.fpart == 0.0 and i64(r.ipart) & 1 == 1
}
-test "pow32" {
+test "math.pow" {
const epsilon = 0.000001;
- // assert(math.approxEq(f32, pow32(0.0, 3.3), 0.0, epsilon)); // TODO: Handle div zero
- assert(math.approxEq(f32, pow32(0.8923, 3.3), 0.686572, epsilon));
- assert(math.approxEq(f32, pow32(0.2, 3.3), 0.004936, epsilon));
- assert(math.approxEq(f32, pow32(1.5, 3.3), 3.811546, epsilon));
- assert(math.approxEq(f32, pow32(37.45, 3.3), 155736.703125, epsilon));
- assert(math.approxEq(f32, pow32(89.123, 3.3), 2722489.5, epsilon));
-}
+ // assert(math.approxEq(f32, pow(f32, 0.0, 3.3), 0.0, epsilon)); // TODO: Handle div zero
+ assert(math.approxEq(f32, pow(f32, 0.8923, 3.3), 0.686572, epsilon));
+ assert(math.approxEq(f32, pow(f32, 0.2, 3.3), 0.004936, epsilon));
+ assert(math.approxEq(f32, pow(f32, 1.5, 3.3), 3.811546, epsilon));
+ assert(math.approxEq(f32, pow(f32, 37.45, 3.3), 155736.703125, epsilon));
+ assert(math.approxEq(f32, pow(f32, 89.123, 3.3), 2722489.5, epsilon));
-test "pow64" {
- const epsilon = 0.000001;
- // assert(math.approxEq(f32, pow32(0.0, 3.3), 0.0, epsilon)); // TODO: Handle div zero
- assert(math.approxEq(f64, pow64(0.8923, 3.3), 0.686572, epsilon));
- assert(math.approxEq(f64, pow64(0.2, 3.3), 0.004936, epsilon));
- assert(math.approxEq(f64, pow64(1.5, 3.3), 3.811546, epsilon));
- assert(math.approxEq(f64, pow64(37.45, 3.3), 155736.7160616, epsilon));
- assert(math.approxEq(f64, pow64(89.123, 3.3), 2722490.231436, epsilon));
+ // assert(math.approxEq(f32, pow(f64, 0.0, 3.3), 0.0, epsilon)); // TODO: Handle div zero
+ assert(math.approxEq(f64, pow(f64, 0.8923, 3.3), 0.686572, epsilon));
+ assert(math.approxEq(f64, pow(f64, 0.2, 3.3), 0.004936, epsilon));
+ assert(math.approxEq(f64, pow(f64, 1.5, 3.3), 3.811546, epsilon));
+ assert(math.approxEq(f64, pow(f64, 37.45, 3.3), 155736.7160616, epsilon));
+ assert(math.approxEq(f64, pow(f64, 89.123, 3.3), 2722490.231436, epsilon));
}
std/special/builtin.zig
@@ -60,7 +60,7 @@ fn generic_fmod(comptime T: type, x: T, y: T) -> T {
if (ex == 0) {
i = ux <<% exp_bits;
while (i >> bits_minus_1 == 0) : ({ex -= 1; i <<%= 1}) {}
- ux <<%= twosComplementCast(uint, -ex + 1);
+ ux <<%= @bitCast(u32, -ex + 1);
} else {
ux &= @maxValue(uint) >> exp_bits;
ux |= 1 <<% digits;
@@ -68,7 +68,7 @@ fn generic_fmod(comptime T: type, x: T, y: T) -> T {
if (ey == 0) {
i = uy <<% exp_bits;
while (i >> bits_minus_1 == 0) : ({ey -= 1; i <<%= 1}) {}
- uy <<= twosComplementCast(uint, -ey + 1);
+ uy <<= @bitCast(u32, -ey + 1);
} else {
uy &= @maxValue(uint) >> exp_bits;
uy |= 1 <<% digits;
@@ -95,9 +95,9 @@ fn generic_fmod(comptime T: type, x: T, y: T) -> T {
// scale result up
if (ex > 0) {
ux -%= 1 <<% digits;
- ux |= twosComplementCast(uint, ex) <<% digits;
+ ux |= @bitCast(u32, ex) <<% digits;
} else {
- ux >>= twosComplementCast(uint, -ex + 1);
+ ux >>= @bitCast(u32, -ex + 1);
}
if (T == f32) {
ux |= sx;
@@ -116,8 +116,3 @@ fn isNan(comptime T: type, bits: T) -> bool {
unreachable;
}
}
-
-// TODO this should be a builtin function and it shouldn't do a ptr cast
-fn twosComplementCast(comptime T: type, src: var) -> T {
- return *@ptrCast(&const @IntType(T.is_signed, @typeOf(src).bit_count), &src);
-}