/*
Copyright 2016 Ian Jauslin

Licensed 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.
*/

/*
  Base functions for integration

  see integral_*.h for the values taken by INTEGRAL_FUNC, etc...
*/

#include <pthread.h>

// compute the integral of a real function of 1 variable using the Gauss-Legendre scheme
int INTEGRAL_FUNC(integrate_gauss) (INTEGRAL_FLOAT_TYPE* out, int (*func)(INTEGRAL_FLOAT_TYPE*, INTEGRAL_FLOAT_TYPE, void*), INTEGRAL_FLOAT_TYPE lower, INTEGRAL_FLOAT_TYPE upper, INTEGRAL_FLOATARRAY_TYPE abcissa, INTEGRAL_FLOATARRAY_TYPE weights, void* extra_args);

// multithreaded version
int INTEGRAL_FUNC(integrate_gauss_multithread) (INTEGRAL_FLOAT_TYPE* out, int (*func)(INTEGRAL_FLOAT_TYPE*, INTEGRAL_FLOAT_TYPE, void*), INTEGRAL_FLOAT_TYPE lower, INTEGRAL_FLOAT_TYPE upper, INTEGRAL_FLOATARRAY_TYPE abcissa, INTEGRAL_FLOATARRAY_TYPE weights, void* extra_args, unsigned int threads, array_pthread_t* thread_ids);
// per-thread function
void* INTEGRAL_FUNC(integrate_gauss_thread) (void* args);

// smart management of temporary variables: initialize as many as needed but allow them to be re-used instead of freeing them
#ifdef INTEGRAL_FLOAT_INIT
int INTEGRAL_FUNC(integrate_gauss_smarttmp) (INTEGRAL_FLOAT_TYPE* out, int (*func)(INTEGRAL_FLOAT_TYPE*, INTEGRAL_FLOAT_TYPE, void*), INTEGRAL_FLOAT_TYPE lower, INTEGRAL_FLOAT_TYPE upper, INTEGRAL_FLOATARRAY_TYPE abcissa, INTEGRAL_FLOATARRAY_TYPE weights, INTEGRAL_FLOATARRAY_TYPE* tmps, void* extra_args);
// multithreaded version with smart management of temporary variables (only for datatypes that need to be initialized)
int INTEGRAL_FUNC(integrate_gauss_smarttmp_multithread) (INTEGRAL_FLOAT_TYPE* out, int (*func)(INTEGRAL_FLOAT_TYPE*, INTEGRAL_FLOAT_TYPE, void*), INTEGRAL_FLOAT_TYPE lower, INTEGRAL_FLOAT_TYPE upper, INTEGRAL_FLOATARRAY_TYPE abcissa, INTEGRAL_FLOATARRAY_TYPE weights, INTEGRAL_FLOATARRAY_TYPE* tmps, void* extra_args, unsigned int threads, array_pthread_t* thread_ids);
// per-thread function
void* INTEGRAL_FUNC(integrate_gauss_smarttmp_thread) (void* args);
#endif

// compute the abcissa and weights for the Gauss-Legendre numerical integration scheme
int INTEGRAL_FUNC(gauss_legendre_weights) (unsigned int order, INTEGRAL_FLOAT_TYPE tolerance, unsigned int maxiter, INTEGRAL_FLOATARRAY_TYPE* abcissa, INTEGRAL_FLOATARRAY_TYPE* weights);

// wrapper functions to evaluate the legendre polynomial and its derivative
int INTEGRAL_FUNC(legendre_wrapper) (INTEGRAL_FLOAT_TYPE* out, INTEGRAL_FLOAT_TYPE in, void* legendre);
int INTEGRAL_FUNC(deriv_legendre_wrapper) (INTEGRAL_FLOAT_TYPE* out, INTEGRAL_FLOAT_TYPE in, void* legendre);