Concerning #783: Refactor SetNonzeros
Fixes #783
Concerning #783: Refactoring SetNonzeros symbolic evaluation
Concerning #783: Refactoring SetNonzeros symbolic evaluation (2)
Revert "Concerning #783: Refactoring SetNonzeros symbolic evaluation (2)"

This reverts commit 9247c070c6e611bf2191db2c59a3af0e6d9f4d57.