qmckl/src/qmckl_context.org

Context

• Header
• Source
• Test
• Context
  • Header
  • Source
  • Test
  • qmckl_context_create
    • Header
    • Source
    • Test
  • qmckl_context_copy
    • Header
    • Source
    • Test
  • qmckl_context_previous
    • Header
    • Source
    • Test
  • qmckl_context_destroy
    • Header
    • Source
    • Test
• Precision
  • qmckl_context_update_precision
  • qmckl_context_update_range
  • qmckl_context_set_precision
  • qmckl_context_set_range
  • qmckl_context_get_precision
  • qmckl_context_get_range
• End of files
  • Header
  • Test

This file is written in C because it is more natural to express the context in C than in Fortran.

3 files are produced:

• a header file : qmckl_context.h
• a source file : qmckl_context.c
• a test file : test_qmckl_context.c

Header

#ifndef QMCKL_CONTEXT_H
#define QMCKL_CONTEXT_H
#include "qmckl.h"

Source

#include <stdlib.h>   /* malloc */
#include "qmckl_context.h"

Test

#include "qmckl_context.h"
#include "qmckl_test.h"
int main() {
qmckl_exit_code  rc;  /* return code */
rc = QMCKL_SUCCESS;

Context

The context variable is a handle for the state of the library, and is stored in the following data structure, which can't be seen outside of the library. To simplify compatibility with other languages, the pointer to the internal data structure is converted into a 64-bit signed integer, defined in the qmckl_context type. A value of 0 for the context is equivalent to a NULL pointer.

Header

/* 64-bit integer */
typedef long long int qmckl_context ;

Source

typedef struct qmckl_context_struct {
struct qmckl_context_struct * prev;
int precision;
int range;
} qmckl_context_struct;

Test

We declare here the variables used in the tests.

qmckl_context  context;
qmckl_context  new_context;

qmckl_context_create

To create a new context, use qmckl_context_create().

• On success, returns a pointer to a context using the qmckl_context type
• Returns 0 upon failure to allocate the internal data structure

Header

qmckl_context qmckl_context_create();

Source

qmckl_context qmckl_context_create() {

qmckl_context_struct*  context;

context = (qmckl_context_struct*) malloc (sizeof(qmckl_context_struct));
if (context == NULL) {
return (qmckl_context) 0;
}

context->prev      = NULL;
context->precision = QMCKL_DEFAULT_PRECISION;
context->range     = QMCKL_DEFAULT_RANGE;

return (qmckl_context) context;
}

Test

context = qmckl_context_create();
if (context == (qmckl_context) 0) {
eprintf("qmckl_context_create\n");
rc = QMCKL_FAILURE;
}
if ( ((qmckl_context_struct*) new_context)->precision != QMCKL_DEFAULT_PRECISION ) {
eprintf("qmckl_context_copy: No access to data\n");
rc = QMCKL_FAILURE;
}

qmckl_context_copy

This function makes a shallow copy of the current context.

• Copying the 0-valued context returns 0
• On success, returns a pointer to the new context using the qmckl_context type
• Returns 0 upon failure to allocate the internal data structure for the new context

Header

qmckl_context qmckl_context_copy(const qmckl_context context);

Source

qmckl_context qmckl_context_copy(const qmckl_context context) {

qmckl_context_struct* old_context;
qmckl_context_struct* new_context;

if (context == (qmckl_context) 0) {
 return (qmckl_context) 0;
}

new_context = (qmckl_context_struct*) malloc (sizeof(qmckl_context_struct));
if (new_context == NULL) {
 return (qmckl_context) 0;
}

old_context = (qmckl_context_struct*) context;

new_context->prev      = old_context;
new_context->precision = old_context->precision;
new_context->range     = old_context->range;

return (qmckl_context) new_context;
}

Test

new_context = qmckl_context_copy(context);
if (new_context == (qmckl_context) 0) {
eprintf("qmckl_context_copy: Allocation failure\n");
rc = QMCKL_FAILURE;
}
if (new_context == context ) {
eprintf("qmckl_context_copy: Same pointer\n");
rc = QMCKL_FAILURE;
}
if ( ((qmckl_context_struct*) new_context)->precision != QMCKL_DEFAULT_PRECISION ) {
eprintf("qmckl_context_copy: No access to data\n");
rc = QMCKL_FAILURE;
}

qmckl_context_previous

Returns the previous context

• On success, returns the ancestor of the current context
• Returns 0 for the initial context
• Returns 0 for the 0-valued context

Header

qmckl_context qmckl_context_previous(const qmckl_context context);

Source

qmckl_context qmckl_context_previous(const qmckl_context context) {

qmckl_context_struct* ctx;

if (context == (qmckl_context) 0) {
 return (qmckl_context) 0;
}

ctx = (qmckl_context_struct*) context;
return (qmckl_context) ctx->prev;
}

Test

if (qmckl_context_previous(new_context) == (qmckl_context) 0) {
eprintf("qmckl_context_copy: Null pointer\n");
rc = QMCKL_FAILURE;
}
if (qmckl_context_previous(new_context) != context) {
eprintf("qmckl_context_copy: Wrong pointer\n");
rc = QMCKL_FAILURE;
}
if (qmckl_context_previous(context) != (qmckl_context) 0) {
eprintf("qmckl_context_copy: Expected null pointer (1)\n");
rc = QMCKL_FAILURE;
}
if (qmckl_context_previous((qmckl_context) 0) != (qmckl_context) 0) {
eprintf("qmckl_context_copy: Expected null pointer (2)\n");
rc = QMCKL_FAILURE;
}

qmckl_context_destroy

Destroys the current context, leaving the ancestors untouched.

• Succeeds if the current context is properly destroyed
• Fails otherwise
• Fails is the 0-valued context is given in argument

The context given in parameter is overwritten by the 0-valued context, so a pointer is passed to the function.

Header

qmckl_exit_code qmckl_context_destroy(qmckl_context * context);

Source

qmckl_exit_code qmckl_context_destroy(qmckl_context *context) {

qmckl_context_struct* ctx;

ctx = (qmckl_context_struct*) *context;

if (ctx == NULL) {
 return QMCKL_FAILURE;
}

free(ctx);
*context = (qmckl_context) 0;
return QMCKL_SUCCESS;
}

Test

if (new_context == (qmckl_context) 0) {
eprintf("qmckl_context_destroy: new_context is NULL\n");
rc = QMCKL_FAILURE;
}
if (qmckl_context_destroy(&new_context) == QMCKL_FAILURE) {
eprintf("qmckl_context_destroy: Unable to destroy the new_context\n");
rc = QMCKL_FAILURE;
}
if (new_context != (qmckl_context) 0) {
eprintf("qmckl_context_destroy: new_context should be NULL\n");
rc = QMCKL_FAILURE;
}
if (qmckl_context_destroy((qmckl_context) 0) == QMCKL_SUCCESS) {
eprintf("qmckl_context_destroy: Failure expected with NULL pointer\n");
rc = QMCKL_FAILURE;
}

Precision

The following functions set and get the expected required precision and range. precision should be an integer between 2 and 53, and range should be an integer between 2 and 11.

The setter functions functions return a new context as a 64-bit integer. The getter functions return the value, as a 32-bit integer. The update functions return QMCKL_SUCCESS or QMCKL_FAILURE.

qmckl_context_update_precision

qmckl_exit_code qmckl_context_update_precision(const qmckl_context context, int precision);

qmckl_exit_code qmckl_context_update_precision(const qmckl_context context, int precision) {
qmckl_context_struct* ctx;

if (precision <  2) return QMCKL_FAILURE;
if (precision > 53) return QMCKL_FAILURE;

ctx = (qmckl_context_struct*) context;
if (ctx == NULL) return QMCKL_FAILURE;

ctx->precision = precision;
return QMCKL_SUCCESS;
}

qmckl_context_update_range

qmckl_exit_code qmckl_context_update_range(const qmckl_context context, int range);

qmckl_exit_code qmckl_context_update_range(const qmckl_context context, int range) {
qmckl_context_struct* ctx;

if (range <  2) return QMCKL_FAILURE;
if (range > 11) return QMCKL_FAILURE;

ctx = (qmckl_context_struct*) context;
if (ctx == NULL) return QMCKL_FAILURE;

ctx->range = range;
return QMCKL_SUCCESS;
}

qmckl_context_set_precision

qmckl_context qmckl_context_set_precision(const qmckl_context context, int precision);

qmckl_context qmckl_context_set_precision(const qmckl_context context, const int precision) {
qmckl_context new_context;

new_context = qmckl_context_copy(context);
if (new_context == 0) return 0;

if (qmckl_context_update_precision(context, precision) == QMCKL_FAILURE) return 0;

return new_context;
}

qmckl_context_set_range

qmckl_context qmckl_context_set_range(const qmckl_context context, int range);

qmckl_context qmckl_context_set_range(const qmckl_context context, int range) {
qmckl_context new_context;

new_context = qmckl_context_copy(context);
if (new_context == 0) return 0;

if (qmckl_context_update_range(context, range) == QMCKL_FAILURE) return 0;

return new_context;
}

qmckl_context_get_precision

int qmckl_context_get_precision(const qmckl_context context);

int qmckl_context_get_precision(const qmckl_context context) {
qmckl_context_struct* ctx;
ctx = (qmckl_context_struct*) context;
return ctx->precision;
}

qmckl_context_get_range

int qmckl_context_get_range(const qmckl_context context);

int qmckl_context_get_range(const qmckl_context context) {
qmckl_context_struct* ctx;
ctx = (qmckl_context_struct*) context;
return ctx->range;
}

End of files

Header

#endif

Test

  return QMCKL_SUCCESS;
}