Mathcad 13 features a number of improvements to promote worksheet quality, increase calculation speed, and provide traceability. In some cases, these changes have caused incompatibilities with previous versions. In most cases, they provide clearer, faster, or more stable ways of achieving the same functionality. For complete information on these changes, see the Migration Guide Tutorial included with the product.

Feature	Mathcad 13	Mathcad 12	Mathcad 11
Determinant Operator	Right-click to select the algorithm.	Right-click to select the algorithm.	Determinant/absolute value operator autodetects shape of argument.
Calculation Speed of Programs Creating Large Matrices	Preallocating matrices is recommended in programs.	Preallocating matrices is required in programs.	Preallocating matrices is recommended in programs.
Solve Blocks Find Whole Vectors	Solve blocks only solve for whole vector or use scalar parameters.	Solve blocks only solve for whole vector or use scalar parameters.	Solve blocks can solve for single element of a vector; results are misleading.
Simultaneous versus Sequential Multiple Array Assignments	Array assignments of interdependent variables are evaluated simultaneously. A worksheet compatibility switch exists to change the behaviour to match Mathcad 11.	Array assignments of interdependent variables are evaluated simultaneously.	Array assignments of interdependent variables are evaluated sequentially.
Arrays Elements Must Exist Before They Can Be Referenced	Undefined array elements cannot be used in any context. Assign the last desired element to zero-pad the array.	Undefined array elements cannot be used in any context. Assign the last desired element to zero-pad the array.	Assigning an indexed array to itself for undefined elements zero-pads the array.
Matrices Cannot Contain Functions and Scalars	Mathcad array elements must be either values or functions, and functions must have the same signature.	Mathcad array elements must be either values or functions, and functions must have the same signature.	Any Mathcad types can be mixed as array elements.
Singular Value Functions Replaced	The svd2 function packs results into a single nested vector, making it easier to use results.	The svd and svds functions find U, V and singular value vector, respectively.	The svd and svds functions find U, V and singular value vector, respectively.