package expm: matrix powers within a product of matrices: operation precedence
I want to double check that for M and N kxk mtrices and v a k-vector M%^%2%*%N%*%v is not automatically read as (M%^%2)%*%N%*%v or M%*%N%^%2%*%v is not automatically read as M%*%(N%^%2)%*%v or both I had been assuming the usual precedence (powers first, then multiplication) applies for matrix powers and multiplication in expm. I was getting unexpected results. In desperation I tried putting in the parentheses and seem to be getting much more reasonable answers. But I am so surprised that the matrix power operation is, apparently, not automatically given precedence over the matrix multiplication operation that I do not trust that adding parentheses has cured my bug. Maybe I am still making some other mistake instead. Can anyone confirm that in fact the parentheses are (sometimes?) essential? I could not find any documentation, one way or the other, just definitions of the power operator and of matrix exponentials. TIA Rainer K. Sachs, Prof emertitus of math -- View this message in context: http://r.789695.n4.nabble.com/package-expm-matrix-powers-within-a-product-of-matrices-operation-precedence-tp4669733.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.