Changeset 21275

Timestamp:

10/15/16 14:29:50 (9 years ago)

Author:

cborstad

Message:

BUG: principal stress convention is to sort by algebraic (not absolute) value

Location:

issm/trunk-jpl/src/m/mech

Files:

• mechanicalproperties.m (modified) (2 diffs)
• mechanicalproperties.py (modified) (2 diffs)

issm/trunk-jpl/src/m/mech/mechanicalproperties.m

@@ -93 +93 @@
         %eigen values and vectors
         [directions,value]=eig(stress);
-        %sort by absolute value of eigenvalue in descending order
-        [val,idx]=sort(abs(diag(value)),'descend');
+        %sort by algebraic value of eigenvalue (not absolute value) in descending order
+        [val,idx]=sort(diag(value),'descend');
         %re-order eigenvalues and associated vectors 
         value=value(idx,idx);
@@ -102 +102 @@
         [directions,value]=eig(strain);
         %same for strainrate
-        [val,idx]=sort(abs(diag(value)),'descend');
+        [val,idx]=sort(diag(value),'descend');
         value=value(idx,idx);
         directions=directions(:,idx);

issm/trunk-jpl/src/m/mech/mechanicalproperties.py

@@ -109 +109 @@
                 #eigenvalues and vectors for stress
                 value,directions=np.linalg.eig(stress);
-                idx=abs(value).argsort()[::-1] # sort in descending order
+                idx=value.argsort()[::-1] # sort in descending algebraic (not absolute) order
                 value=value[idx]
                 directions=directions[:,idx]
@@ -117 +117 @@
                 #eigenvalues and vectors for strain
                 value,directions=np.linalg.eig(strain);
-                idx=abs(value).argsort()[::-1] # sort in descending order
+                idx=value.argsort()[::-1] # sort in descending order
                 value=value[idx]
                 directions=directions[:,idx]