Find minimum and maximum values of a function matlab. I want to use MATLAB special features.
Find minimum and maximum values of a function matlab May 5, 2015 · How can I find the maximum value of a function in MATLAB? And that function has some subject to constrain criteria also. Based Mar 17, 2024 · I have to matrices A and B which both of them are p*q matrices. The fminsearch command can find a single vector of values that will minimize a multi-dimensional function given some Apr 15, 2025 · I'm trying to find the max and min values of a table, and the times that each max and min occurred, what function/syntax would I use to find these values? table = 24×4 table t wsp1 Oct 20, 2020 · I've created some formulas and a function that is composed of if and elseif statements and plots a graph of it. Please let me know how to convert this or use a different code, thanks. Here's an example of how you can use it:. Mar 31, 2018 · I am trying to use min () and max () to find the minimum and maximum values of a vector (attached to this post if you would like to try) According to the Mathworks website, using minVal = min (FHNout); and maxVal = max (FHNout); should work. It will give you the maximum (and indirectly the minimum) values and their index locations. Nov 1, 2023 · The min () function in MATLAB is an essential tool for finding the smallest value in an array or matrix. Oct 1, 2017 · I'm trying to write an M-file that finds the max/min of a function, given a certain range. The indexes are just time points found with the 'find' function but are about 200 and 400. See full list on mathworks. The output structure shows the number of iterations. Oct 30, 2018 · [minval,minindex] = min (meandata (N4index:P6index)); Where meandata is a vector representing a time averaged data series. Since I wanted one singe number I performed max and min operations again. Write the following function as a file, and save the file as scalarobjective. e. The MinMax block outputs either the minimum or the maximum element or elements of the inputs. I tried using 'xmin' and 'ymin' but it outputs all of the values instead of the ones I am looking for. Jul 21, 2012 · Hi, I have a set of data which oscillates between minimums and maximum values. All you need to do is use the max () function. which parameter) o Minimize a function that is specified by a separate function file. The MinMax block ignores any input value that is NaN, except when every input value is NaN. For example, the following code produces a row vector 'M' that contains the maximum value of each column of 'A', which is 3 for the first column and 4 for the second column. Jan 6, 2023 · To determine the maximum and minimum values of every month and the corresponding dates on which these values occurred, you can use the resample function in MATLAB. ) The max/min plot dips down to nearly zero and then climbs up steadily with the Absolute valued function. The output xmax is the value of x that maximizes the function, and -ymax is the value of the maximum. The fminbnd command can find a single independent value that will minimize a one-dimensional function over a specific domain. We then use fminbnd to find the minimum of the negated function -fun(x) over the interval [0, 10], which gives us the maximum of fun(x). Oct 29, 2018 · I have many vectors that contain force and joint moment data and I need to find the max values without losing the sign. This MATLAB function returns the minimum elements of an array. One common method to find the maximum value of a function in MATLAB is through optimization using the built-in function fminsearch. My equation is y = (1*x^4)/4+ (4*x^3)/3- 5* (x^2)/2 over -3<=x<=3. For example, if the values were [2 6 -7] I'd need to get -7, if the vector wa May 18, 2018 · If you are asking how to find the global minimum and maximum of an arbitrary function, then this is not something that matlab can do. Mar 10, 2018 · so i have this text file (hwk3_input. A function accepts a point x and returns a real scalar representing the value of the objective function at x. I want to see the trend of changing of min and max values over time. The output structure also shows the number of function evaluations, which the iterative display shows, but the chosen plot function does not. . Each dimension represents a different parameter for the measurement. In fact, it's not something that anybody knows how to do generically. However, when trying these commands, I get the following error: ??? This MATLAB function returns a logical array whose elements are 1 (true) when a local minimum is detected in the corresponding element of A. Jun 16, 2013 · I have a 4D array of measurements in MATLAB. Apr 3, 2019 · Hi, So I have the following code and I want to find the min and max of the function. The output of these commands will be a row vector (default) which will have max/min values of each column in that array/matrix. I want to use MATLAB special features. In this comprehensive guide, we will explore the syntax, parameters, and key applications of MATLAB‘s min () function. When all input values are NaN, the output is NaN, either as a scalar or the value of each output vector element. This MATLAB function returns the minimum value of the scalar-valued univariate spline in f on its basic interval. Nov 26, 2024 · The "min" and "max" functions in MATLAB return the index of the minimum and maximum values, respectively, as an optional second output argument. Not only can they help you ind the minimum and the maximum, but they can also help you find the index to Jul 23, 2025 · To find the maximum and minimum values of a function we find the derivatives of the given function. You can use the index to extract the corresponding a1. Here's an example code snippet that shows how to use fminsearch to find the maximum value of a function f(x) within a given range: Sep 27, 2017 · Introduction This page discusses two different ways of getting MATLAB to find the minimum of a function (versus a data set) - fminbnd and fminsearch. If your function is linear, then you run the following code and optimize your function: May 22, 2020 · Finding the value of inputs that minimzes or maximizes the objective function value is an optimization problem. If ‘y’ is the vector that produced the plot, to find the maxima and minima: Nov 21, 2023 · Here, I demonstrate how to use the min () and max () functions in MATLAB for data analysis. txt) that is very large, 1140 X 1 I have a matrix, i called this matrix A. Mar 19, 2022 · How to find minimum and maximum pixel value in Learn more about image, image processing, digital image processing, array, arrays MATLAB Mar 7, 2019 · I will assume you need to find both the maximum value in b1 as well as its corresponding a1 value. Jan 19, 2022 · I would like to show the max and minimum value of a graph in Matlab figure Nov 1, 2021 · One option is to use ‘findpeaks’ in the Signal Processing Toolbox. Example follows: Jul 18, 2021 · I'm trying to find the max and min of a function over a function, but I can't seem to figure out how. I want to compare each member of A and B like A (i,j) and B (i,j) and put the maximum in a matrix like C it the same position of (i,j) and the minimum in the other matrix like D in the same position of (i,j). However I am needing for the graph to show the max and min of the curve and I am unsure of how to do so. If your function is linear, then you run the following code and optimize your function: This MATLAB function returns the maximum elements of an array. In order to do that, it seems that I need to extract the local min and local maximums. This handy function has many uses for data analysis and processing. Oct 7, 2009 · The "min" and "max" functions in MATLAB return the index of the minimum and maximum values, respectively, as an optional second output argument. I know there are other ways of doing it, including using the derivative of the function, but I would much rather assistance in finding out what is incorrect in my algorithm, which tests surrounding points in order to find maxima and minima. The min and max values change slightly over time. Apr 28, 2025 · The max () and min () functions find the maximum and minimum values respectively in an array, along a given dimension. file to find the maximum and minimum number in array **do not use the built in functions in matlab** ? i know how to find Aug 13, 2018 · I have this function below and I need to calculate the minimum and maximum of this function U, and also plotting the maximum and minimum value in 3D graph together with the function. This MATLAB function returns a logical array whose elements are 1 (true) when a local maximum is detected in the corresponding element of A. This MATLAB function returns the minimum value minA and maximum value maxA in an array. How can I wri Sep 7, 2023 · For example, to find the index of maximum value of matrix, we can use a combination of the 'max ()' and 'find ()' functions. If the function f (x) ≤ f (a) for all x ∈ D then f (a) is the maximum value of the function and if f (x) ≥ f (a) for all x ∈ D then f (a) is the minimum value of the function. m on your MATLAB® path. Sketch the given surface and show the extreme values (using matlab). com Dec 27, 2023 · The bounds() function returns the minimum and maximum values within a matrix, multidimensional array or data sequence with a single operation. Dec 12, 2016 · I am trying to find positive and negative maximum and minimum in an array. I want to find the maximum and minimum value and the index (i. If I procede with this code then "acos (- 33^ (1/2)/8 - 1/8)" shows in every following calculation. The value of exitflag is 1, meaning fminsearch likely converged to a local minimum. The max () function will return both the maximum value, and the index position of the value. The iterative display and the plot show this information as well. Sep 6, 2013 · 2. Lets say I have a Matrix A= [1 -2 5;3 7 -9,4 6 8] if I use max and min functions on A,I get max (A)= [4 7 8] and min (A)= [1 -2 -9]. Apr 22, 2020 · and I want a numerical value because I need to use the scalar maximum for other calculations. For large datasets, this greatly improves efficiency over coding manual searches or applying basic functions like min() and max() separately. May 22, 2020 · Finding the value of inputs that minimzes or maximizes the objective function value is an optimization problem. Let's say I have defined an equation in the command window like so: > y = @(x) -1*x^2 + 3 y = In this example, we define the function fun to maximize, which is a quadratic with a maximum at x=5. I need to use for loop to find the max and min value Jun 1, 2021 · Find the local maximum and minimum values and saddle points of f (x, y) = x^3 + 3xy + y^3 . On the other hand, if we want to find the index of minimum value of a matrix, then we use the combination of the 'min ()' and 'find ()' functions. Jul 10, 2011 · hi every one I really need your help in this question write a function m. You choose whether the block outputs the minimum or maximum values by setting the Function parameter. cgzkdgk0buwexoxhbvgsoytwsz3qki6ep8hydckoxcjfi64