Find zvalue corresponding to x and y points matlab. Cb and cs values at t5, as well as i need to find the t and cb values when cs 0. Nov 07, 20 absfxtarget will be closer to 0 at the place where the values in fx are closer to the target value. Learn more about curve fit, gauss, curve fitting, value, find, matlab, x given y matlab. I am looking to find the code which gives me an x value from the line graph given a y.
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. Finding interpolated x value given y value when data. Finding yvalue of a function with corresponding xvalue given. This function was defined using the comando polyfit based on some points, resulting in a fourth order equation. My question is that, given a value of x and y, how can i find the value of z at this point. This matlab function returns the classification loss by resubstitution l, the insample classification loss, for the support vector machine svm classifier svmmodel using the training data stored in svmmodel. If matlab cant find a solution it will return an empty symbol.
You may receive emails, depending on your notification preferences. I have already tried to find it by using plot x, y but dont know how. I can find the value of y at half maximum, but given the steepness of the slope and the fact that my data is in an array, i am having difficulty finding the 4 x values which correspond to this y value. Include the following with your homework submission. 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. And comparing doubles in this manner is not generally a good idea due to precision, see why is 0. Thanks for contributing an answer to mathematics stack exchange.
When plotted, there are two peaks where the slope in those regions is very steep. Ece 1010 ece problem solving i interpolation and 6 curve. When i use interp1, it returns the grid vectors are not strictly monotonic increasing. May 22, 2019 i plot x y graph gaussian function and want to get the x axis value will be two points in this case at a certain y axis value half of the maximum i tried this but it didnt work. There are several possibly y values for any given x value, so interp1 would not be a valid way to get an answer.
If there isnt a data set, it would be nice to get the value of how the plot line. How to use matlab to determine f3f5 for a function and interval of your choice. Find zvalue corresponding to x and y points matlab answers. The return value of the excludedata is a logical vector which you can use to index into elements as you have done for the x values. Would be really nice to get an answer on my simple question. But perhaps you have a figure file and lost the x and y values. Jan 11, 2017 how to change the values of x or y axis in matlab. Official matlab subreddit a place to discuss the matlab programming language and its implementation. I would like to generate the x value using a corresponding random y value, these random values are within the range of y, from a graph which i have created using the pchip function, but i want the generated x value to stay within a specific range. Find x value corresponding to y value in a equation and. So basically if you want to plot anything, of course you need to have the data set. I was writing a code for taylors series in matlab so i thought what if i input the function from user itself and the solve for that.
Mar 26, 2018 so basically if you want to plot anything, of course you need to have the data set. How to find the x at a certain value of yx equation. Question about finding y value for certain x value of a. How to find x value given y value and show the point on a. Find value of x, from max y graph matlab answers matlab. Create symbolic functions matlab symfun mathworks benelux. I want to use an interp1 function, but that will only give me y values. Pick a number from an array with a certain probability. How to find value of y if i know x value from grap matlab. 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 value 8 is located.
Then, you find a value y that corresponds to a value x using interp1. If you plot x versus y, the values are known and therefore the problem has not relation to the plotting. You can dock figures by default on your matlab workplace by creating a startup. Solving a equation for the x value with the given y value matlab. Therefore, i want to give a commend that orders to give the yvalue at certain x value.
How do i use matlab to find an x value given a known y. I then want to find the corresponding x value that goes along with the. All supporting pencil and paper work needed to develop the necessary equations. The polyval function is used for evaluating a polynomial at a specified value. Defining function handles in matlab matlab answers matlab. How to find vector elements between two values, efficiently. You should go to that link, and click the download button, and download the. Be aware, that the above method replies one value only, even if the maximum value appears several times in the data. To include extra parameters in your function, see the example root of function with extra parameter and the section parameterizing functions. I was going around mathworks forums and i found this tip i wanted to share with you guys. 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. How to get maximum value from any plotx,y in matlab quora. I want to know the y value from my graph example x 10 to 11, till 10 to 11 in. 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.
To define a function in matlab you can do following syntax of given function. Apr 15, 2014 also when i ploted, the significant figures in the plotting graph is not long enough that i can not compare the value for instance, using data crusor for x 2, y 0. Find value of x, from max y graph follow 45 views last 30 days andrew on 17 oct 2014. To get this, assign the result of the call to max to a two element vector instead of. Apr 26, 2016 i have looked around and most people recommend either using find which i cant because the new y value wont definitely be in the given y values or interp1. Learn more about finding data points, find x from y. Oct 08, 2017 i want to let the program calculate the x value when y0. Equations and systems solver matlab solve mathworks.
Find signal location using similarity search matlab. How to find the value for x for given y on a function. Asking for help, clarification, or responding to other answers. Question about finding y value for certain x value of a plot matlab. Stack overflow for teams is a private, secure spot for you and your coworkers to find and share information. Matlab represents polynomials as row vectors containing coefficients ordered by descending powers. You clicked a link that corresponds to this matlab command. View questions and answers from the matlab central community. Run the command by entering it in the matlab command window. Finding specific data point x for given y matlab answers. Find x from y in a graph matlab answers matlab central.
To evaluate fx at different values of x, you can create an. To solve an equation funx cx, instead solve fun2x funx cx 0. The fzero function will then start there to search for a zerocrossing. By default, interp1 interpolates linearly, that is, it returns the values as if the dots in the plot were connected by straight lines. Dec 02, 2015 i have plotted a matlab graph using a long matrix. Plotting a line xconstant matlab answers matlab central. 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. Even if you flip the x and y, its still multivalued. The location in fx that is closest to the target will have the smallest absolute difference compared to the target.
I have a matrix, x5 6 9 8 4 y8 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 value 8 is located. How can i find x for given y value in a fitted curve. I need to find all elements that fall between 2 values l,u in a matrix a with 2. To directly find the elements in x that satisfy the condition x x x x find x find on a logical matrix. How to create a function in matlab given the y values. How to find maximum value in a plot matlab answers matlab. Find the x value from a graph, created using pchip, given the. I then made an anonymous function and used fplot to graph its outputsf in this case for every x value. Learn more about beamwidth of antenna, x value corresponding to y matlab.
What is a good way to plot a straight line parallel to yaxis for a particular x value. In the example below, the indices corresponding to the desired locations xfind,yfind would be ix 2 4 4 6, iy 2 6 8 9. X and the corresponding class labels stored in svmmodel. A printout of the resulting surface and its linearization. How to find corresponding y values to x values when only. I have already tried to find it by using plotx,y but dont know how. It needs to have an initial estimate of the solution as do all iterative gradientdescent algorithms, such as nonlinear parameter estimation or function minimisation algorithms such as fminsearch. I now want to know how i can find the corresponding. 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. Given a vector list of locations, how can i find their indices within xedges,yedges. Find indices and values of nonzero elements matlab find. Anonymous function handles often called anonymous functions represent single inline. Binomial cumulative distribution function matlab binocdf.
Say your x and y values that you used for plotting are stored in xdata and ydata, respectively. Finding xvalues from found yvalues matlab answers matlab. Ive defined several variables and made x an array of values. I would like to find the x value corresponding to y0. Therefore, i want to give a commend that orders to give the yvalue at certain xvalue. Now, i just need to find the x value that give me f90. Learn more about interp1, interpolation, intersection, find x, logarithmic, log10.
I want it to span 02 the value im looking for is around 1. I believe you can follow a similar assignment to index into the yvalues. Matlab displays to four decimal places by default, but using the command format you can change how values are displayed. The return value of the excludedata is a logical vector which you can use to index into elements as you have done for the xvalues. I want to let the program calculate the x value when y 0. Given that abcd is an isosceles trapezoid, find x and y.
Find index to x,y pairs matlab answers matlab central. In the example below, the lower left location value would be 20, 2. 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. Find detailed answers to questions about coding, structures, functions, applications and. How do i use matlab to find an x value given a known y value. I have the previously pictured plot, and i have found the half intensity values using ginput.
This matlab function solves the equation eqn for the variable var. Then this equation was integrated, resulting in a fifth order equation. Finding x value corresponds to a particular y value. If y is a matrix, then stem plots all elements in a row against the same x value, and the xaxis scale ranges from 1 to the number of rows in y. When you execute find with a relational operation like x 1, it is important to remember that the result of the relational operation is a logical matrix of ones and zeros.
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