On Dec 30, 2011, at 8:26 PM, Rick T wrote:
> On Fri, Dec 30, 2011 at 2:19 PM, Ben Abbott <
address@hidden> wrote:
>> On Dec 30, 2011, at 7:08 PM, Rick T wrote:
>>
>> > Greetings All
>> >
>> > I'm trying to have the x value and y value next to the peak and valley on a plot can someone assist
>> >
>> > t= linspace(0,2*pi,8000);
>> > freq=10;
>> > y=sin(t*freq)+cos(t*freq*1.3);
>> > y=y';
>> > y2=y*3+y*4+y*2;
>> > yf=(y2(:,1)/max(abs(y2(:,1)))*1); %keep at 1, amplitude levels
>> > plot(yf)
>>
>> I haven't tested this.
>>
>> [~, mn] = min (yf);
>> [~, mx] = max (yf);
>> plot (t, yf, t(mn), yf(mn), "s", t(mx), yf(mx), "s")
>> text (t(mn), yf(mn), sprintf ("min = %f", yf(mn)), "verticalalignment", "top", "horizontalalighment", "center")
>> text (t(mx), yf(mx), sprintf ("max = %f", yf(mx)), "verticalalignment", "bottom", "horizontalalighment", "center")
>>
>> Ben
>
> thanks but it comes back with an error
>
> parse error near line 10 of file test_plot.m
> syntax error
> >>> [~, mn] = min (yf);
> ^
> >>>error: source: error sourcing file `test_plot.m'
>
> this was the code I used
>
> t= linspace(0,2*pi,8000);
> freq=10;
> y=sin(t*freq)+cos(t*freq*1.3);
> y=y';
> y2=y*3+y*4+y*2;
> yf=(y2(:,1)/max(abs(y2(:,1)))*1); %keep at 1, amplitude levels
> %plot(yf)
> [~, mn] = min (yf);
> [~, mx] = max (yf);
> plot (t, yf, t(mn), yf(mn), "s", t(mx), yf(mx), "s")
> text (t(mn), yf(mn), sprintf ("min = %f", yf(mn)), "verticalalignment", "top", "horizontalalighment", "center")
> text (t(mx), yf(mx), sprintf ("max = %f", yf(mx)), "verticalalignment", "bottom", "horizontalalighment", "center")