![]() ![]() You can access the intrinsic math functions by adding Imports System.Math to your file or project. What is the error? Are the matrix arguments wrong, or is the operator wrong? Mathematica won't guess, so it reports an error to the user (programmer) to fix it.The following table shows non-intrinsic math functions that can be derived from the intrinsic math functions of the System.Math object. Specifically, the arctan is the inverse of the tangent. the two matrices do not have the same dimensions to the number cannot be matched up. This just came to mind while I was messing around on Wolfram Alpha. It so happens that Times can be applied to matrices, meaning that the multiplication is to be threaded across matching numbers into the two matrices. We specified * ( Times), so it will attempt to use *. Here, Mathematica is not making any assumptions. Note how the product operator has been quietly re-interpreted as the matrix-multiplying Dot operator.Īlternatively, we can use the unambiguous formal Mathematica syntax that makes no assumptions, reporting errors instead: By starting an input expression with =, we can tell Mathematica that we want it to infer our meaning from free-form input: The good news is that Mathematica supports both use cases directly. This is not a valid Mathematica expression, yet WolframAlpha takes it in stride. One gets the same result by entering, for example: ![]() The fact that it resembles an Mathematica expression is coincidental. WolframAlpha is treating the exhibited expression as free-form input. In the second case, inferencing is harmful since there is no human in the loop to spot any misinterpretation. I've also tried this form in Alpha, with no luck. In Mathematica I can perform the equivalent: h x g InverseFunction f x h' x without any difficulties. In the first case, inferencing is welcomed as the user can immediately see whether the interpretation was correct. WolframAlpha now just recognises g as a variable, and will not allow me to use it as an inverse. programmers) to write code intended to be executed by machine as part of larger composite systems. But it also allows Mathematica users (i.e. It shares the need to interact with a human just like WolframAlpha. In contrast, the Mathematica system serves two goals. This is a very reasonable assumption given that WWW users might not be familiar with the ins and outs of Mathematica syntax. In this case, WolframAlpha correctly inferred that the product operation in the expression is actually a matrix multiplication. As such, it uses inference heavily to try to make sense of what the user entered. WolframAlpha is primarily aimed at interpreting input from a human and delivering a response back to that human. Mathematica (or WolframAlpha), Octave, SymboLab, or whatever. Longer Version: Why is there a difference? You may use inverse methods, row reduction methods, or whatever you think is best (and. Note how Mathematica made sense of two alternative free-form expressions of the same thing, and converted each into the same valid expression involving the Dot operator. You can get Mathematica to convert WolframAlpha-style free-form input into a valid expression using CTRL+ = or by starting an input expression with =: ![]()
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