Finding xvalues from found yvalues matlab answers matlab. Ive defined several variables and made x an array of values. I have already tried to find it by using plotx,y but dont know how. Specify optional commaseparated pairs of name,value arguments. Be aware, that the above method replies one value only, even if the maximum value appears several times in the data. I have plotted a graph based on known sets of data for x and y.
I have the previously pictured plot, and i have found the half intensity values using ginput. Name is the argument name and value is the corresponding value. I already have a program which calls the data and plot the spectra. If i can extract the x and y values in those regions, i can fit the curves. Lia ismembertola,b,tol returns an array containing logical 1 true where the elements of a are within tolerance of the elements in b. Follow 42 views last 30 days michael on 2 may 2014.
The only way i can think to do it is to solve for x by hand and then type that into matlab but there has to be a simpler way. Btw, i need the x and yaxis data to be presented in rows instead of columns, and i cant seem to get the linest equation right when i take the data values in. Note that there can be the max value at more than one location. How to get maximum value from any plotx,y in matlab quora. You would need to iterate with different starting values. You can also use newtzero from file exchange that can find more solutions. You need to solve nonlinear equation for given y and unknown x. Determining xvalue with given yvalue from scatter chart. How to find the minimum points coordination in matlab. I want to know the y value from my graph example x 10 to 11, till 10 to 11 in y axis i. The location in fx that is closest to the target will have the smallest absolute difference compared to the target.
I know how to find the location in the the x and y matrices where these values occur, but im not sure how get the z value from this. How do i get matlab to show me the x value on my max y value that i have in my function and in my graph. Note that scilab function can only return two output values and matlab one can return a third value that can be computed according to the first two output matrices as explained in matlab help. Finding x values for known y values from a gaussian fit in. I want to know the y value from my graph example x 10 to 11, till 10 to 11 in. I plot xy graph gaussian function and want to get the xaxis value will be two points in this case at a certain yaxis value half of the. I want to let the program calculate the x value when y0. Members of set within tolerance matlab ismembertol. I want to know the y value from my graph example x 10 to 11, till 10 to 11 in y axis i have to mark. Question about finding y value for certain x value of a plot matlab.
Each time you press the up and downarrow keys, the name of the function being evaluated appears in the border at the top of the. Finding yvalue of a function with corresponding xvalue given. I have a matrix, x 5 6 9 8 4 y 8 7 2 1 9 if i plot this and i need to get position of the x value corresponds to y1, that means in which row the x. Y asinx returns the inverse sine sin1 of the elements of x in radians. How to find the value of a function on the ti84 plus. Downloads trial software contact sales pricing and licensing. So basically if you want to plot anything, of course you need to have the data set. Binomial cumulative distribution function matlab binocdf. Then, you find a value y that corresponds to a value x using interp1. So there are some restrictions, but only those imposed by the continuity and differentiability of the function, and the. Find the highest value of y for each x value matlab answers.
The result is a 1by0 empty matrix, which i guess is a null. If matlab cant find a solution it will return an empty symbol. As this program is written by someone else, i am not able to find where the x and y values are. At the end, use disp and string to print findings as such. Finding largest y value with corresponding x value. Is there any other way to find the min value other than zero and also to find its index. Finding approximate y values for corresponding x values in matlab. I want to choose some regions and do exponential fit. Matlab can also calculate the remainder of an integer division operation. Finding maximum y value corresponding to same x values. How do i use matlab to find an x value given a known y. To get the rows and columns instead of linear indexes, you can use ind2subs or find. How to get the y values between two x values on a plotmatlab. I have then added a horizontal line to the plot at the y value where i want to find out the corresponding x values shown in red on the plot.
If youre interested in the initial estimate for fzero, that can be anything, provided that 1 the function is defined at the initial estimate, 2 is defined for all values between it and the value of x at the zerocrossing, and 3 that a zerocrossing exists. By default, interp1 interpolates linearly, that is, it returns the values as if the dots in the plot were connected by straight lines. The function find doesnt help as there is no exact value of y at 0. I got the value using the following code but i have the nan value in pbest in loops it is giving errors. How to find value of y if i know x value from grap.
Finding index for minimum value in array matlab answers. If there isnt a data set, it would be nice to get the value of how the plot line. Say your x and y values that you used for plotting are stored in xdata and ydata, respectively. If matlab finds several solutions it returns a vector of solutions. Therefore, i want to give a commend that orders to give the yvalue at certain xvalue. Even if you flip the x and y, its still multivalued.
How to find maximum value in a plot matlab answers. I am trying to find the beamwidth of a rectangular patch antenna. Learn more about beamwidth of antenna, x value corresponding to y matlab. Find x value corresponding to y value in a equation and. If you just want a quick and dirty answer without showing any work, type the equation into a graphing calculator, experiment to find window settings that show the equation, then use the calctools to find the minimum. You can also find the value of a function by pressing trace, entering an x value, and pressing enter. How to find x value given y value and show the point on a. I need to find a way such that for any x value, matlab will find the closest x value on the graph and give me the corresponding y value. Therefore, i want to give a commend that orders to give the yvalue at certain x value. In other words, using polyval, and using the equation derived from polyfit, when x 1. I have a matrix, x 5 6 9 8 4 y 8 7 2 1 9 if i plot this and i need to get position of the x value corresponds to y 1, that means in which row the x value 8 is located. If your plot is available in another form, please specify it exactly.
Finding x value corresponds to a particular y value. How to use matlab to determine f3f5 for a function and interval of your choice. Y acosx returns the inverse cosine cos1 of the elements of x in radians. I then made an anonymous function and used fplot to graph its outputsf in this case for every x value. For real values of x in the interval 1, 1, acosx returns values in the interval 0. How to find the minimum value of the function mathfxx. You may receive emails, depending on your notification preferences. Now, i just need to find the x value that give me f90. I now want to know how i can find the corresponding. I am looking to find the code which gives me an x value from the line graph given a y. To interpolate x2 from y2, reverse the usual x,y argument order, and use y,x instead, as i did here. And comparing doubles in this manner is not generally a good idea due to precision, see why is 0. Find zvalue corresponding to x and y points matlab answers. Inverse sine in radians matlab asin mathworks switzerland.
You can specify several name and value pair arguments in any order as name1,value1. To solve an equation funx cx, instead solve fun2x funx cx 0. I have plotted the equations, but i have to find the value of x corresponding to the value at y0. Predict y values from x values matlab answers matlab central. How to find value of y if i know x value from grap matlab. Two values, u and v, are within tolerance if absuv find x given y. Lets say you have x time and y velocity in order to find the maximum value, you need to employ some matlab functions max and find. E edgeens,x,y returns the classification edge for ens with data x and classification y. Now, if the desired x is not in your x array, then you can use interp1 to get the interpolatedestimated y value for that x. There are several possibly y values for any given x value, so interp1 would not be a valid way to get an answer. The plot shows your original data as a green line, and the interpolated points as blue stars.
I need a code that steps through x values from xmin and xmax with step size, calculates the value of f x and keeps track of the largest y value and the corresponding x value. Id like to spit out an array of the max y coordinate that corresponds to each x coordinate. Official matlab subreddit a place to discuss the matlab programming language and its implementation. I now want to know how i can find the corresponding x values. For real values of x in the interval 1, 1, asinx returns values in the interval. The data values are indicated by circles terminating each stem. If y is a vector, then the xaxis scale ranges from 1 to lengthy. I need to find the index for the minimum value in pbest other than 0. To include extra parameters in your function, see the example root of function with extra parameter and the section parameterizing functions.
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