question: public static void assertEquals ( String msg , RealMatrix expected , RealMatrix observed , double tolerance ) { Assert . assertNotNull ( msg + "\nObserved should not be null" , observed ) ; if ( expected . getColumnDimension ( ) != observed . getColumnDimension ( ) || expected . getRowDimension ( ) != observed . getRowDimension ( ) ) { StringBuilder messageBuffer = new StringBuilder ( msg ) ; messageBuffer . append ( "\nObserved has incorrect dimensions." ) ; messageBuffer . append ( "\nobserved is " + observed . getRowDimension ( ) + " x " + observed . getColumnDimension ( ) ) ; messageBuffer . append ( "\nexpected " + expected . getRowDimension ( ) + " x " + expected . getColumnDimension ( ) ) ; Assert . fail ( messageBuffer . toString ( ) ) ; } RealMatrix delta = expected . subtract ( observed ) ; if ( delta . getNorm ( ) >= tolerance ) { StringBuilder messageBuffer = new StringBuilder ( msg ) ; messageBuffer . append ( "\nExpected: " + expected ) ; messageBuffer . append ( "\nObserved: " + observed ) ; messageBuffer . append ( "\nexpected - observed: " + delta ) ; Assert . fail ( messageBuffer . toString ( ) ) ; } }
target:  verifies that two matrices are close (1-norm) 