src/test/maxima/special/reference/gamma.mac

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * This script generates reference ("exact") values for the gamma function.
 * The generated values are stored sequentially in a binary file, as follows
 * x[0], f(x[0]), x[1], f(x[1]), ...
 * where f is the function being sampled.
 */
kill(all);

fpprec : 64;
f(x) := gamma(x);

sample(x, name) := block(
  y : [],
  for i : 1 while i <= length(x) do y : endcons(float(f(x[i])), y),
  xy : join(float(x), y),
  stream : openw_binary(name),
  write_binary_data(xy, stream),
  close(stream)
  );

x : makelist(bfloat(i / 1024), i, -5119, -4097);
sample(x, "gamma-01.dat");

x : makelist(bfloat(i / 1024), i, -4095, -3073);
sample(x, "gamma-02.dat");

x : makelist(bfloat(i / 1024), i, -3071, -2049);
sample(x, "gamma-03.dat");

x : makelist(bfloat(i / 1024), i, -2047, -1025);
sample(x, "gamma-04.dat");

x : makelist(bfloat(i / 1024), i, -1023, -1);
sample(x, "gamma-05.dat");

x : makelist(bfloat(i / 1024), i, 1, 8192);
sample(x, "gamma-06.dat");

x : makelist(bfloat(i / 64), i, 513, 9024);
sample(x, "gamma-07.dat");