Build CRE Gather

Using CRE Gather trajectory (calculated with Mcretrajec.c),
select the closest trace to a given m,h pair in that trajectory,
in the interpolated data cube. Those will form a CRE Gather section.

Mcretrajec.c

@@ -1,4 +1,4 @@
-/* Versão 1.0 - Calculate CRE trajectory on m,h plane given zero offset CRS parameters (RNIP, BETA)
+/* Version 1.0 - Calculate CRE trajectory on m,h plane given zero offset CRS parameters (RNIP, BETA)
 
 Programer: Rodolfo A. C. Neves (Dirack) 31/08/2019
 

Mgetcregather.c

@@ -0,0 +1,116 @@
+/* Version 1.0 - Build CRE gather given m,h CRE trajectory coordinates and interpolated data cube
+
+This program searches for the closest trace for each m,h pair given in the interpolated data cube. 
+
+Programer: Rodolfo A. C. Neves (Dirack) 04/09/2019
+
+Email:  rodolfo_profissional@hotmail.com  
+
+License: GPL-3.0 <https://www.gnu.org/licenses/gpl-3.0.txt>.
+
+*/
+
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <rsf.h>
+
+int main(int argc, char* argv[])
+{
+
+	float*** t; // Data cube A(m,h,t)
+	float** creGather;
+	float* m; // CMP
+	bool verb;
+	float dm; // CMP sampling
+	float om; // CMP axis origin
+	int nm; // Number of CMP samples
+	float dh; // Offset sampling
+	float oh; // Offset axis origin
+	int nh; // Offset number of samples
+	float dt; // Time sampling
+	float ot; // Time axis origin
+	int nt; // Number of time samples
+	int i,j; // loop counter
+	int cre_n; // Number of CRE Gather traces
+	float cre_d; // CRE Gather sampling
+	float cre_o; // CRE Gather axis origin
+	int trac_m; // CMP sample index
+
+	/* RSF files I/O */  
+	sf_file in, out, out_m, cremh;
+
+	/* RSF files axis */
+	sf_axis ax,ay,az,am;
+
+	sf_init(argc,argv);
+
+	in = sf_input("in"); // Data cube A(m,h,t)
+	cremh = sf_input("cremh"); /* CRE Gather m(h) coordinates */
+	out = sf_output("out"); // CRE Gather
+	out_m = sf_output("m"); // CRE Gather CMP coordinate
+
+	if (!sf_histint(in,"n1",&nt)) sf_error("No n1= in input file");
+	if (!sf_histfloat(in,"d1",&dt)) sf_error("No d1= in input file");
+	if (!sf_histfloat(in,"o1",&ot)) sf_error("No o1= in input file");
+	if (!sf_histint(in,"n2",&nh)) sf_error("No n2= in input file");
+	if (!sf_histfloat(in,"d2",&dh)) sf_error("No d2= in input file");
+	if (!sf_histfloat(in,"o2",&oh)) sf_error("No o2= in input file");
+	if (!sf_histint(in,"n3",&nm)) sf_error("No n3= in input file");
+	if (!sf_histfloat(in,"d3",&dm)) sf_error("No d3= in input file");
+	if (!sf_histfloat(in,"o3",&om)) sf_error("No o3= in input file");
+
+	if(!sf_histint(cremh,"n1",&cre_n)) sf_error("No n1= in cremh file");
+	if(!sf_histfloat(cremh,"d1",&cre_d)) sf_error("No d1= in cremh file");
+	if(!sf_histfloat(cremh,"o1",&cre_o)) sf_error("No o1= in cremh file");
+
+	if(! sf_getbool("verb",&verb)) verb=0;
+	/* 1: active mode; 0: quiet mode */
+
+	if (verb) {
+
+		sf_warning("Active mode on!!!");
+		sf_warning("CRE gather coordinates m(h) (cremh file): ");
+		sf_warning("n1=%i d1=%f o1=%f",cre_n,cre_d,cre_o);
+		sf_warning("Input file dimensions: ");
+		sf_warning("n1=%i d1=%f o1=%f",nt,dt,ot);
+		sf_warning("n2=%i d2=%f o2=%f",nh,dh,oh);
+		sf_warning("n3=%i d3=%f o3=%f",nm,dm,om);
+	}
+
+	/* Read data cube */
+	t=sf_floatalloc3(nt,nh,nm);
+	sf_floatread(t[0][0],nh*nm*nt,in);
+
+	m = sf_floatalloc(cre_n);
+	sf_floatread(m,cre_n,cremh);
+	creGather = sf_floatalloc2(nt,cre_n);
+
+	for(i=0;i<cre_n;i++){
+		trac_m = (int)(m[i]/dm);
+
+		for(j=0;j<nt;j++){
+			creGather[i][j] = t[trac_m][i][j];
+		}
+	}
+
+	/* eixo = sf_maxa(n,o,d)*/
+	ax = sf_maxa(nt, ot, dt);
+	ay = sf_maxa(nh, oh, dh);
+	az = sf_maxa(1, 0, 1);
+
+	/* sf_oaxa(arquivo, eixo, índice do eixo) */
+	sf_oaxa(out,ax,1);
+	sf_oaxa(out,ay,2);
+	sf_oaxa(out,az,3);
+	sf_floatwrite(creGather[0],cre_n*nt,out);
+
+	/* eixo do vetor m */
+	am = sf_maxa(cre_n,oh,dh);
+	sf_oaxa(out_m,am,1);
+	sf_oaxa(out_m,az,2);
+	sf_oaxa(out_m,az,3);
+	sf_floatwrite(m,cre_n,out_m);
+
+	exit(0);
+}