authorgravatar for lewis.gaul@gmail.comLewis Gaul <lewis.gaul@gmail.com> 2024-05-25 22:05:26+01:00
committergravatar for andrew@ziglang.orgAndrew Kelley <andrew@ziglang.org> 2025-07-17 05:04:59+02:00
logda8974e57f3581d7302efa3cacbd0d55f6c87bd4
tree05d0c045bbb2088b8fbe8bb7dd44e91112a524de
parent9da19e51ea1da7cf6746dbdf8340248a77ce362f

Add tests for exp(), noting last-bit discrepancy for exp(1.0) with math.e

1 files changed, 89 insertions(+), 20 deletions(-)

lib/compiler_rt/exp.zig+89-20
...@@ -10,6 +10,7 @@ const arch = builtin.cpu.arch;...@@ -10,6 +10,7 @@ const arch = builtin.cpu.arch;
10const math = std.math;10const math = std.math;
11const mem = std.mem;11const mem = std.mem;
12const expect = std.testing.expect;12const expect = std.testing.expect;
13const expectEqual = std.testing.expectEqual;
13const common = @import("common.zig");14const common = @import("common.zig");
1415
15pub const panic = common.panic;16pub const panic = common.panic;
...@@ -211,32 +212,100 @@ pub fn expl(x: c_longdouble) callconv(.c) c_longdouble {...@@ -211,32 +212,100 @@ pub fn expl(x: c_longdouble) callconv(.c) c_longdouble {
211 }212 }
212}213}
213214
214test "exp32" {215test "expf() special" {
215 const epsilon = 0.000001;216 try expectEqual(expf(0.0), 1.0);
217 try expectEqual(expf(-0.0), 1.0);
218 try expectEqual(expf(1.0), math.e);
219 try expectEqual(expf(math.ln2), 2.0);
220 try expectEqual(expf(math.inf(f32)), math.inf(f32));
221 try expectEqual(expf(-math.inf(f32)), 0.0);
222 try expect(math.isNan(expf(math.nan(f32))));
223 try expect(math.isNan(expf(math.snan(f32))));
224}
216225
217 try expect(expf(0.0) == 1.0);226test "expf() sanity" {
218 try expect(math.approxEqAbs(f32, expf(0.0), 1.0, epsilon));227 try expectEqual(expf(-0x1.0223a0p+3), 0x1.490320p-12);
219 try expect(math.approxEqAbs(f32, expf(0.2), 1.221403, epsilon));228 try expectEqual(expf(0x1.161868p+2), 0x1.34712ap+6);
220 try expect(math.approxEqAbs(f32, expf(0.8923), 2.440737, epsilon));229 try expectEqual(expf(-0x1.0c34b4p+3), 0x1.e06b1ap-13);
221 try expect(math.approxEqAbs(f32, expf(1.5), 4.481689, epsilon));230 try expectEqual(expf(-0x1.a206f0p+2), 0x1.7dd484p-10);
231 try expectEqual(expf(0x1.288bbcp+3), 0x1.4abc80p+13);
232 try expectEqual(expf(0x1.52efd0p-1), 0x1.f04a9cp+0);
233 try expectEqual(expf(-0x1.a05cc8p-2), 0x1.54f1e0p-1);
234 try expectEqual(expf(0x1.1f9efap-1), 0x1.c0f628p+0);
235 try expectEqual(expf(0x1.8c5db0p-1), 0x1.1599b2p+1);
236 try expectEqual(expf(-0x1.5b86eap-1), 0x1.03b572p-1);
237 try expectEqual(expf(-0x1.57f25cp+2), 0x1.2fbea2p-8);
238 try expectEqual(expf(0x1.c7d310p+3), 0x1.76eefp+20);
239 try expectEqual(expf(0x1.19be70p+4), 0x1.52d3dep+25);
240 try expectEqual(expf(-0x1.ab6d70p+3), 0x1.a88adep-20);
241 try expectEqual(expf(-0x1.5ac18ep+2), 0x1.22b328p-8);
242 try expectEqual(expf(-0x1.925982p-1), 0x1.d2acc0p-2);
243 try expectEqual(expf(0x1.7221cep+3), 0x1.9c2ceap+16);
244 try expectEqual(expf(0x1.11a0d4p+4), 0x1.980ee6p+24);
245 try expectEqual(expf(-0x1.ae41a2p+1), 0x1.1c28d0p-5);
246 try expectEqual(expf(-0x1.329154p+4), 0x1.47ef94p-28);
222}247}
223248
224test "exp64" {249test "expf() boundary" {
225 const epsilon = 0.000001;250 try expectEqual(expf(0x1.62e42ep+6), 0x1.ffff08p+127); // The last value before the result gets infinite
251 try expectEqual(expf(0x1.62e430p+6), math.inf(f32)); // The first value that gives inf
252 try expectEqual(expf(0x1.fffffep+127), math.inf(f32)); // Max input value
253 try expectEqual(expf(0x1p-149), 1.0); // Min positive input value
254 try expectEqual(expf(-0x1p-149), 1.0); // Min negative input value
255 try expectEqual(expf(0x1p-126), 1.0); // First positive subnormal input
256 try expectEqual(expf(-0x1p-126), 1.0); // First negative subnormal input
257 try expectEqual(expf(-0x1.9fe368p+6), 0x1p-149); // The last value before the result flushes to zero
258 try expectEqual(expf(-0x1.9fe36ap+6), 0.0); // The first value at which the result flushes to zero
259 try expectEqual(expf(-0x1.5d589ep+6), 0x1.00004cp-126); // The last value before the result flushes to subnormal
260 try expectEqual(expf(-0x1.5d58a0p+6), 0x1.ffff98p-127); // The first value for which the result flushes to subnormal
226261
227 try expect(exp(0.0) == 1.0);
228 try expect(math.approxEqAbs(f64, exp(0.0), 1.0, epsilon));
229 try expect(math.approxEqAbs(f64, exp(0.2), 1.221403, epsilon));
230 try expect(math.approxEqAbs(f64, exp(0.8923), 2.440737, epsilon));
231 try expect(math.approxEqAbs(f64, exp(1.5), 4.481689, epsilon));
232}262}
233263
234test "exp32.special" {264test "exp() special" {
235 try expect(math.isPositiveInf(expf(math.inf(f32))));265 try expectEqual(exp(0.0), 1.0);
236 try expect(math.isNan(expf(math.nan(f32))));266 try expectEqual(exp(-0.0), 1.0);
267 // TODO: Accuracy error - off in the last bit in 64-bit, disagreeing with GCC
268 // try expectEqual(exp(1.0), math.e);
269 try expectEqual(exp(math.ln2), 2.0);
270 try expectEqual(exp(math.inf(f64)), math.inf(f64));
271 try expectEqual(exp(-math.inf(f64)), 0.0);
272 try expect(math.isNan(exp(math.nan(f64))));
273 try expect(math.isNan(exp(math.snan(f64))));
237}274}
238275
239test "exp64.special" {276test "exp() sanity" {
240 try expect(math.isPositiveInf(exp(math.inf(f64))));277 try expectEqual(exp(-0x1.02239f3c6a8f1p+3), 0x1.490327ea61235p-12);
241 try expect(math.isNan(exp(math.nan(f64))));278 try expectEqual(exp(0x1.161868e18bc67p+2), 0x1.34712ed238c04p+6);
279 try expectEqual(exp(-0x1.0c34b3e01e6e7p+3), 0x1.e06b1b6c18e64p-13);
280 try expectEqual(exp(-0x1.a206f0a19dcc4p+2), 0x1.7dd47f810e68cp-10);
281 try expectEqual(exp(0x1.288bbb0d6a1e6p+3), 0x1.4abc77496e07ep+13);
282 try expectEqual(exp(0x1.52efd0cd80497p-1), 0x1.f04a9c1080500p+0);
283 try expectEqual(exp(-0x1.a05cc754481d1p-2), 0x1.54f1e0fd3ea0dp-1);
284 try expectEqual(exp(0x1.1f9ef934745cbp-1), 0x1.c0f6266a6a547p+0);
285 try expectEqual(exp(0x1.8c5db097f7442p-1), 0x1.1599b1d4a25fbp+1);
286 try expectEqual(exp(-0x1.5b86ea8118a0ep-1), 0x1.03b5728a00229p-1);
287 try expectEqual(exp(-0x1.57f25b2b5006dp+2), 0x1.2fbea6a01cab9p-8);
288 try expectEqual(exp(0x1.c7d30fb825911p+3), 0x1.76eeed45a0634p+20);
289 try expectEqual(exp(0x1.19be709de7505p+4), 0x1.52d3eb7be6844p+25);
290 try expectEqual(exp(-0x1.ab6d6fba96889p+3), 0x1.a88ae12f985d6p-20);
291 try expectEqual(exp(-0x1.5ac18e27084ddp+2), 0x1.22b327da9cca6p-8);
292 try expectEqual(exp(-0x1.925981b093c41p-1), 0x1.d2acc046b55f7p-2);
293 try expectEqual(exp(0x1.7221cd18455f5p+3), 0x1.9c2cde8699cfbp+16);
294 try expectEqual(exp(0x1.11a0d4a51b239p+4), 0x1.980ef612ff182p+24);
295 try expectEqual(exp(-0x1.ae41a1079de4dp+1), 0x1.1c28d16bb3222p-5);
296 try expectEqual(exp(-0x1.329153103b871p+4), 0x1.47efa6ddd0d22p-28);
297}
298
299test "exp() boundary" {
300 try expectEqual(exp(0x1.62e42fefa39efp+9), 0x1.fffffffffff2ap+1023); // The last value before the result gets infinite
301 try expectEqual(exp(0x1.62e42fefa39f0p+9), math.inf(f64)); // The first value that gives inf
302 try expectEqual(exp(0x1.fffffffffffffp+1023), math.inf(f64)); // Max input value
303 try expectEqual(exp(0x1p-1074), 1.0); // Min positive input value
304 try expectEqual(exp(-0x1p-1074), 1.0); // Min negative input value
305 try expectEqual(exp(0x1p-1022), 1.0); // First positive subnormal input
306 try expectEqual(exp(-0x1p-1022), 1.0); // First negative subnormal input
307 try expectEqual(exp(-0x1.74910d52d3051p+9), 0x1p-1074); // The last value before the result flushes to zero
308 try expectEqual(exp(-0x1.74910d52d3052p+9), 0.0); // The first value at which the result flushes to zero
309 try expectEqual(exp(-0x1.6232bdd7abcd2p+9), 0x1.000000000007cp-1022); // The last value before the result flushes to subnormal
310 try expectEqual(exp(-0x1.6232bdd7abcd3p+9), 0x1.ffffffffffcf8p-1023); // The first value for which the result flushes to subnormal
242}311}