/*  heat.h

  Chris Nevison
	June 24, 1997

	This file contains specifications for functions for setting 
  up and solving the heat equation on a rectangular surface, 
  using the ??????????? iterative method.
	The boundary values of the rectangle are held constant.
*/

int CreateDblMat(int numrows, int numcols, double initval,
                 double * * * mat);
/* pre:  *mat is uninitialized or NULL                  */
/* post: *mat is a numrows x numcols matrix of doubles  */
/*       with value initval.                            */
/*       if there is insufficient memory, return 0      */
/*       otherwise return 1                             */

void UpdateMat(double * * matin, int numrows, int numcols,
               double * * matout, double * maxdif);
/* pre:  matin and matout are initialized numrows x numcols */
/*       arrays of doubles.                                 */
/* post: matout contains values such that the boundary      */
/*       values are the same as the boundary values for     */
/*       matin and interior values are the average of the   */
/*       four (or eight) nearest neighbors.  maxdif is the  */
/*       maximum difference between corresponding values    */
/*       of the two arrays.                                 */

void SolveHeat(double * row0, double * rowmax,
               double * col0, double * colmax, 
               int numrows, int numcols,
               double tol, int maxiter,
               double * * * mat);
/* pre:  row0 and rowmax each have numcols entries,          */
/*       col0 and colmax each have numrows entries,          */
/*       row0[0] = col0[0]; row0[numcols-1] = colmax[0];     */
/*       rowmax[0] = col0[numrows-1];                        */
/*       rowmax[numcols-1] = colmax[[numrows-1];             */
/*       tol > 0; maxiter > 0;                               */
/*       *mat is uninitialized or NULL.                      */
/* post: *mat is a numrows x numcols matrix whose entries    */
/*       of the heat equation with boundary values fixed at  */
/*       the values given by row0, rowmax, col0, and colmax  */
/*       computed using the ?????????? iterative method      */
/*       with accuracy given by tol unless maxiter iterations*/
/*       are reached.                                        */

void FindMinMax(int numrows, int numcols, double * * mat,
                double * minval, double * maxval);
/* pre:  mat is a numrows x numcols array of doubles         */
/* post: minval and maxval are the minimum and maximum       */
/*       values, respectively, in mat.                       */

void ReadHeatBndry(FILE * infile,
                   int * numrows, int * numcols,
                   double * * row0, double * * rowmax,
                   double * * col0, double * * colmax);
/* pre:  infile is open and ready for reading, formatted to  */
/*       contain the number of rows and number of columns    */
/*       for the rectangular region (two ints), followed by  */
/*       the initial values for the first and last rows and  */
/*       the first and last columns of the regions           */
/*       (2 * numcols + 2 * numrows double values)           */
/* post: The number of rows and number of columns have been  */
/*       assigned to the parameters numrows and numcols;     */
/*       row0 and rowmax are each allocated space for        */
/*       numcols double values and col0 and colmax are       */
/*       each allocated space for numrows double values;     */
/*       the first and last row values have been assigned to */
/*       parameters row0 and rowmax, and the first and last  */
/*       column values have been assigned to the parameters  */
/*       col0 and colmax.                                    */
/*       row0[0] = col0[0]; row0[numcols-1] = colmax[0];     */
/*       rowmax[0] = col0[numrows-1];                        */
/*       rowmax[numcols-1] = colmax[numrows-1]               */