// Copyright 2020 Google LLC // // This source code is licensed under the BSD-style license found in the // LICENSE file in the root directory of this source tree. display=hexadecimal !; print("log2(e) =", round(log2(exp(1)), single, RN)); minus_ln2_hi = round(-log(2), single, RN); minus_ln2_lo = round(-log(2) - minus_ln2_hi, single, RN); print("-log(2):hi =", minus_ln2_hi); print("-log(2):lo =", minus_ln2_lo); print("log2(e) * 8 =", round(log2(exp(1)) * 8, single, RN)); minus_ln2_o8_hi = round(-log(2)/8, single, RN); minus_ln2_o8_lo = round(-log(2)/8 - minus_ln2_o8_hi, single, RN); print("-log(2):hi / 8 =", minus_ln2_o8_hi); print("-log(2):lo / 8 =", minus_ln2_o8_lo); lb = round(-log(2)/2, single, RN); ub = round(log(2)/2, single, RN); P = fpminimax(expm1(x), [|1,2,3,4,5|], [|SG...|], [lb; ub], relative, 0); print("Degree-5 P[expm1(x)] with 0 constraint on [-log(2)/2, log(2)/2] =", horner(P)); print(" -log(2)/2 = ", lb); print(" +log(2)/2 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU)); lb = round(-log(2)/2, single, RN); ub = round(log(2)/2, single, RN); P = fpminimax(expm1(x), [|1,2,3,4,5,6|], [|SG...|], [lb; ub], relative, 0); print("Degree-6 P[expm1(x)] with 0 constraint on [-log(2)/2, log(2)/2] =", horner(P)); print(" -log(2)/2 = ", lb); print(" +log(2)/2 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU)); lb = round(-log(2)/2, single, RN); ub = round(log(2)/2, single, RN); P = fpminimax(expm1(x), [|2,3,4,5|], [|SG...|], [lb; ub], relative, 0+x); print("Degree-5 P[expm1(x)] with 0+x constraint on [-log(2)/2, log(2)/2] =", horner(P)); print(" -log(2)/2 = ", lb); print(" +log(2)/2 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU)); lb = round(-log(2)/2, single, RN); ub = round(log(2)/2, single, RN); P = fpminimax(expm1(x), [|2,3,4,5,6|], [|SG...|], [lb; ub], relative, 0+x); print("Degree-6 P[expm1(x)] with 0+x constraint on [-log(2)/2, log(2)/2] =", horner(P)); print(" -log(2)/2 = ", lb); print(" +log(2)/2 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU)); lb = round(-log(2)/8, single, RN); ub = round(log(2)/8, single, RN); P = fpminimax(expm1(x), [|2,3,4|], [|SG...|], [lb; ub], relative, 0+x); print("Degree-4 P[expm1(x)] with 0+x constraint on [-log(2)/8, log(2)/8] =", horner(P)); print(" -log(2)/8 =", lb); print(" +log(2)/8 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU)); lb = round(-log(2)/16, single, RN); ub = round(log(2)/16, single, RN); P = fpminimax(expm1(x), [|1,2,3,4|], [|SG...|], [lb; ub], relative, 0); print("Degree-4 P[expm1(x)] with 0 constraint on [-log(2)/16, log(2)/16] =", horner(P)); print(" -log(2)/16 =", lb); print(" +log(2)/16 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU)); lb = round(-log(2)/16, single, RN); ub = round(log(2)/16, single, RN); P = fpminimax(expm1(x), [|2,3,4|], [|SG...|], [lb; ub], relative, 0+x); print("Degree-4 P[expm1(x)] with 0+x constraint on [-log(2)/16, log(2)/16] =", horner(P)); print(" -log(2)/16 =", lb); print(" +log(2)/16 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU)); lb = round(-log(2)/16, single, RN); ub = round(log(2)/16, single, RN); P = fpminimax(expm1(x), [|1,2,3|], [|SG...|], [lb; ub], relative, 0); print("Degree-3 P[expm1(x)] with 0 constraint on [-log(2)/16, log(2)/16] =", horner(P)); print(" -log(2)/16 =", lb); print(" +log(2)/16 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU)); lb = round(-log(2)/16, single, RN); ub = round(log(2)/16, single, RN); P = fpminimax(expm1(x), [|2,3|], [|SG...|], [lb; ub], relative, 0+x); print("Degree-3 P[expm1(x)] with 0+x constraint on [-log(2)/16, log(2)/16] =", horner(P)); print(" -log(2)/16 =", lb); print(" +log(2)/16 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU)); lb = round(-log(2)/32, single, RN); ub = round(log(2)/32, single, RN); P = fpminimax(expm1(x), [|2,3,4|], [|SG...|], [lb; ub], relative, 0+x); print("Degree-4 P[expm1(x)] with 0+x constraint on [-log(2)/32, log(2)/32] =", horner(P)); print(" -log(2)/32 =", lb); print(" +log(2)/32 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU)); lb = round(-log(2)/32, single, RN); ub = round(log(2)/32, single, RN); P = fpminimax(expm1(x), [|2,3|], [|SG...|], [lb; ub], relative, 0+x); print("Degree-3 P[expm1(x)] with 0+x constraint on [-log(2)/32, log(2)/32] =", horner(P)); print(" -log(2)/32 =", lb); print(" +log(2)/32 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU)); lb = round(-log(2)/64, single, RN); ub = round(log(2)/64, single, RN); P = fpminimax(expm1(x), [|2,3|], [|SG...|], [lb; ub], relative, 0+x); print("Degree-3 P[expm1(x)] with 0+x constraint on [-log(2)/64, log(2)/64] =", horner(P)); print(" -log(2)/64 =", lb); print(" +log(2)/64 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU)); lb = round(-log(2)/64, single, RN); ub = round(log(2)/64, single, RN); P = fpminimax(expm1(x), [|1,2|], [|SG...|], [lb; ub], relative, 0); print("Degree-2 P[expm1(x)] with 0 constraint on [-log(2)/64, log(2)/64] =", horner(P)); print(" -log(2)/64 =", lb); print(" +log(2)/64 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU)); lb = round(-log(2)/128, single, RN); ub = round(log(2)/128, single, RN); P = fpminimax(expm1(x), [|2,3|], [|SG...|], [lb; ub], relative, 0+x); print("Degree-3 P[expm1(x)] with 0+x constraint on [-log(2)/128, log(2)/128] =", horner(P)); print(" -log(2)/128 =", lb); print(" +log(2)/128 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU)); lb = round(-log(2)/128, single, RN); ub = round(log(2)/128, single, RN); P = fpminimax(expm1(x), [|1,2|], [|SG...|], [lb; ub], relative, 0); print("Degree-2 P[expm1(x)] with 0 constraint on [-log(2)/128, log(2)/128] =", horner(P)); print(" -log(2)/128 =", lb); print(" +log(2)/128 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU)); lb = round(-log(2)/256, single, RN); ub = round(log(2)/256, single, RN); P = fpminimax(expm1(x), [|1,2|], [|SG...|], [lb; ub], relative, 0); print("Degree-3 P[expm1(x)] with 0 constraint on [-log(2)/256, log(2)/256] =", horner(P)); print(" -log(2)/256 =", lb); print(" +log(2)/256 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU)); lb = round(-log(2)/512, single, RN); ub = round(log(2)/512, single, RN); P = fpminimax(expm1(x), [|1,2|], [|SG...|], [lb; ub], relative, 0); print("Degree-3 P[expm1(x)] with 0 constraint on [-log(2)/512, log(2)/512] =", horner(P)); print(" -log(2)/512 =", lb); print(" +log(2)/512 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU)); lb = round(-log(2)/512, single, RN); ub = round(log(2)/512, single, RN); // fpminimax fails, manually find the minimum in the vicinity of degree-3 polynomial coefficients P = x * (1 + x * 0x1.FFFFFAp-2); print("Degree-3 P[expm1(x)] with 0+x constraint on [-log(2)/512, log(2)/512] =", horner(P)); print(" -log(2)/512 =", lb); print(" +log(2)/512 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU)); lb = round(-log(2)/1024, single, RN); ub = round(log(2)/1024, single, RN); P = fpminimax(expm1(x), [|1,2|], [|SG...|], [lb; ub], relative, 0); print("Degree-3 P[expm1(x)] with 0 constraint on [-log(2)/1024, log(2)/1024] =", horner(P)); print(" -log(2)/1024 =", lb); print(" +log(2)/1024 =", ub); print(" relative error =", round(dirtyinfnorm(P / expm1(x) - 1, [lb; ub]), single, RU));