Bug: MHD+Fargo+MPI (#295)

fix a bug that lead to segfault when MHD+Fargo+MPI (with X3 domain decomposition) are all activated

This went undetected for a while as the test FargoMHDSpherical was
actually testing for small fargo shifts (less than a cell).

Author: glesur

reference

@@ -508,7 +508,7 @@ void Fargo::ShiftFluid(const real t, const real dt, Fluid<Phys>* hydro) {
             for(int ss = s-m ; ss < s ; ss++) {
               int sc;
               if(haveDomainDecomposition) {
-                sc = ss;
+                sc = ss + maxShift;
               } else {
                 sc = sbeg + modPositive(ss-sbeg,n);
               }
@@ -518,7 +518,7 @@ void Fargo::ShiftFluid(const real t, const real dt, Fluid<Phys>* hydro) {
             for(int ss = s ; ss < s-m ; ss++) {
               int sc;
               if(haveDomainDecomposition) {
-                sc = ss;
+                sc = ss + maxShift;
               } else {
                 sc = sbeg + modPositive(ss-sbeg,n);
               }
@@ -544,7 +544,7 @@ void Fargo::ShiftFluid(const real t, const real dt, Fluid<Phys>* hydro) {
             for(int ss = s-m ; ss < s ; ss++) {
               int sc;
               if(haveDomainDecomposition) {
-                sc = ss;
+                sc = ss + maxShift;
               } else {
                 sc = sbeg + modPositive(ss-sbeg,n);
               }
@@ -554,7 +554,7 @@ void Fargo::ShiftFluid(const real t, const real dt, Fluid<Phys>* hydro) {
             for(int ss = s ; ss < s-m ; ss++) {
               int sc;
               if(haveDomainDecomposition) {
-                sc = ss;
+                sc = ss + maxShift;
               } else {
                 sc = sbeg + modPositive(ss-sbeg,n);
               }
@@ -637,7 +637,7 @@ void Fargo::ShiftFluid(const real t, const real dt, Fluid<Phys>* hydro) {
             for(int ss = s-m ; ss < s ; ss++) {
               int sc;
               if(haveDomainDecomposition) {
-                sc = ss;
+                sc = ss + maxShift;
               } else {
                 sc = sbeg + modPositive(ss-sbeg,n);
               }
@@ -647,7 +647,7 @@ void Fargo::ShiftFluid(const real t, const real dt, Fluid<Phys>* hydro) {
             for(int ss = s ; ss < s-m ; ss++) {
               int sc;
               if(haveDomainDecomposition) {
-                sc = ss;
+                sc = ss + maxShift;
               } else {
                 sc = sbeg + modPositive(ss-sbeg,n);
               }
@@ -672,7 +672,7 @@ void Fargo::ShiftFluid(const real t, const real dt, Fluid<Phys>* hydro) {
           for(int ss = s-m ; ss < s ; ss++) {
             int sc;
             if(haveDomainDecomposition) {
-              sc = ss;
+              sc = ss + maxShift;
             } else {
               sc = sbeg + modPositive(ss-sbeg,n);
             }
@@ -682,7 +682,7 @@ void Fargo::ShiftFluid(const real t, const real dt, Fluid<Phys>* hydro) {
           for(int ss = s ; ss < s-m ; ss++) {
             int sc;
             if(haveDomainDecomposition) {
-              sc = ss;
+              sc = ss + maxShift;
             } else {
               sc = sbeg + modPositive(ss-sbeg,n);
             }

src/dataBlock/fargo.hpp

@@ -1,7 +1,7 @@
 [Grid]
-X1-grid    1  1.0                 16  l  2.0
-X2-grid    1  1.2707963267948965  64  u  1.8707963267948966
-X3-grid    1  0.0                 64  u  6.283185307179586
+X1-grid    1  1.0                 16   l  2.0
+X2-grid    1  1.2707963267948965  16   u  1.8707963267948966
+X3-grid    1  0.0                 128  u  6.283185307179586
 
 [TimeIntegrator]
 CFL         0.5

test/MHD/FargoMHDSpherical/idefix.ini

@@ -53,3 +53,7 @@ def testMe(test):
   test.vectPot=False
   test.mpi=True
   testMe(test)
+
+  test.vectPot=True
+  test.mpi=True
+  testMe(test)