Stress output is a zero array in linear elasticity calculation

[lechanm]

Description

The stress output array for linear elasticity (lElas) calculations is consistently a zero array, regardless of non-zero displacement or strain.
The array S (Array<double> S(nsd, nsd)) is not updated within the if (cPhys == EquationType::phys_lElas) block.
The following code is from post.cpp.

        case OutputNameType::outGrp_stress:
        case OutputNameType::outGrp_cauchy: 
        case OutputNameType::outGrp_mises:
          Array<double> sigma(nsd,nsd);
          Array<double> S(nsd,nsd);

          if (cPhys == EquationType::phys_lElas) {
            if (nsd == 3) {
              double detF = lambda*(ed(0) + ed(1) + ed(2));
              sigma(0,0) = detF + 2.0*mu*ed(0);
              sigma(1,1) = detF + 2.0*mu*ed(1);
              sigma(2,2) = detF + 2.0*mu*ed(2);

              sigma(0,1) = mu*ed(3);
              sigma(1,2) = mu*ed(4);
              sigma(2,0) = mu*ed(5);

              sigma(1,0) = sigma(0,1);
              sigma(2,1) = sigma(1,2);
              sigma(0,2) = sigma(2,0);
            } else {  
              double detF = lambda*(ed(0) + ed(1));
              sigma(0,0) = detF + 2.0*mu*ed(0);
              sigma(1,1) = detF + 2.0*mu*ed(1);
              sigma(0,1) = mu*ed(2);
              sigma(1,0) = sigma(0,1);
            }
          } else if (cPhys == EquationType::phys_ustruct) { 
          } else if (cPhys == EquationType::phys_struct) {
          }
          // 2nd Piola-Kirchhoff stress tensor
          if (outGrp == OutputNameType::outGrp_stress) {
            if (nsd == 3) {
              resl(0) = S(0,0);
              resl(1) = S(1,1);
              resl(2) = S(2,2);
              resl(3) = S(0,1);
              resl(4) = S(1,2);
              resl(5) = S(2,0);
            } else { 
              resl(0) = S(0,0);
              resl(1) = S(1,1);
              resl(2) = S(0,1);
            }

Reproduction

The bug can be reproduced by running the test case for linear elasticity.

Expected behavior

If the strain is non-zero, the stress must also be non-zero.

Additional context

No response

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