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cdf_41.c
Go to the documentation of this file.00001 #include "cdflib.h" 00002 void dinvr(int *status,double *x,double *fx, 00003 unsigned long *qleft,unsigned long *qhi) 00004 /* 00005 ********************************************************************** 00006 00007 void dinvr(int *status,double *x,double *fx, 00008 unsigned long *qleft,unsigned long *qhi) 00009 00010 Double precision 00011 bounds the zero of the function and invokes zror 00012 Reverse Communication 00013 00014 00015 Function 00016 00017 00018 Bounds the function and invokes ZROR to perform the zero 00019 finding. STINVR must have been called before this routine 00020 in order to set its parameters. 00021 00022 00023 Arguments 00024 00025 00026 STATUS <--> At the beginning of a zero finding problem, STATUS 00027 should be set to 0 and INVR invoked. (The value 00028 of parameters other than X will be ignored on this cal 00029 00030 When INVR needs the function evaluated, it will set 00031 STATUS to 1 and return. The value of the function 00032 should be set in FX and INVR again called without 00033 changing any of its other parameters. 00034 00035 When INVR has finished without error, it will return 00036 with STATUS 0. In that case X is approximately a root 00037 of F(X). 00038 00039 If INVR cannot bound the function, it returns status 00040 -1 and sets QLEFT and QHI. 00041 INTEGER STATUS 00042 00043 X <-- The value of X at which F(X) is to be evaluated. 00044 DOUBLE PRECISION X 00045 00046 FX --> The value of F(X) calculated when INVR returns with 00047 STATUS = 1. 00048 DOUBLE PRECISION FX 00049 00050 QLEFT <-- Defined only if QMFINV returns .FALSE. In that 00051 case it is .TRUE. If the stepping search terminated 00052 unsucessfully at SMALL. If it is .FALSE. the search 00053 terminated unsucessfully at BIG. 00054 QLEFT is LOGICAL 00055 00056 QHI <-- Defined only if QMFINV returns .FALSE. In that 00057 case it is .TRUE. if F(X) .GT. Y at the termination 00058 of the search and .FALSE. if F(X) .LT. Y at the 00059 termination of the search. 00060 QHI is LOGICAL 00061 00062 ********************************************************************** 00063 */ 00064 { 00065 E0000(0,status,x,fx,qleft,qhi,NULL,NULL,NULL,NULL,NULL,NULL,NULL); 00066 } /* END */
