![]() The values will be 'str2double' to the variables respectively. I'm very experienced with other languages but transitioning to writing code like this is completely different from anything I've done before. There will be two conditions, either : if out (11) or if out (11). Or, since Times is listable: list = 2 * Range Īnyways, I highly recommend reading some documentation on programming with Mathematica. MATLAB: An Introduction with Applications 5th Edition by Amos Gilat. In fact, we can use pure functions anonymously, and write this whole program in a single line: list = (2*# &) Range Solve the equation for the radius, and use the double command to obtain a numerical. I don't know exactly how/why, but Mathematica 'compiles' (may not be correct word) pure functions so they run even faster. ![]() The line doubleFunction = 2*# & creates a function which behaves very similarly to doubleFunction := 2*x : the # denotes the argument to the function, and the & tells Mathematica that the expression before it is a pure function. However, we can do even better by defining a pure function: list = Range Mathematica automatically threads this over the list so it is much more efficient. Features DoubleCommand 1.5. The third line used the shortcut, which applies the function preceding it to each element of the list following it. DoubleCommand is a quick and easy way to fix this if you use a PC keyboard with your Mac. Next, I'm going to define a function, and map it onto the list: list = Range ĪbsoluteTiming] First, a loop: AbsoluteTiming] = 2*list], ]]]įor a more sophisticated function, this would be painfully slow. I'm going to implement this a few ways and point out how long it takes. This is true, and once a function is created this is probably the way to go, I'm referring to a workflow more than proper development. For example, suppose I had a list of numbers which I wanted to apply some function to:Įdit: It has been pointed out that it is also effective to create a custom package. In general, rather than define your function in an m-file, you define your function in the notebook. It is inspired by Total Commander and features some new ideas. In fact, the modulus of each element is equal to either 0 or 0.2, as shown below for the above sequence of numbers in the array: mod(array,0.2)Īgain, if the values are placed in an array manually and the modulus is taken, the expected value of all 0s is obtained.The paradigm for programming in Mathematica is actually very different from MATLAB. Double Commander is a cross platform open source file manager with two panels side by side, developed by alexx2000. You can use the class function to verify a variables type. The modulus of this array by 0.2 should therefore be everywhere equal to 0. By default, numbers in MATLAB are of the data type double. ![]() Could someone please explain why the equality succeeds if I input the values manually, but fails if the array is generated in the context of a program? I am able to rectify the comparison failure by using an approximate rather than an exact comparison (e.g., (array10.19999)), but this seems unsatisfying.Įdit: The values in the array are generated by iterative addition or subtraction of a constant double (e.g., 0.2). To avoid edge cases when cmd.exe is involved, enclose the overall command in '.' and escape pass-through. If I place the values shown into an array manually (e.g., array=), then the command is successful (i.e., array=10.2 returns 0 0 1 0 0). In Matlab, this function returns a Boolean type value for a Boolean input whereas Scilab function returns a Double type value. Since MatLab's system() function executes the given command line via cmd.exe (which is inefficient in your case, since you don't need shell functionality), use of \' can break the invocation, due to how cmd.exe's parses command lines. If I test for equality to 10.2 (or 10.2000) by the command array=10.2 (or array=10.2000), I return an array of 0s. I suspect that this has to do with the way the double is represented (e.g., 1.0 vs 1.00), but I can't figure it out.įor instance, I have generated an array composed of thousands of double values, the last few of which at some instant in time are given by 10.6000 I am trying to compare an array of doubles to a scalar double for equality, but equality is never recognized under certain circumstances.
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