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2014/10/15 ¤U¤È 10:11:14

iphone Programming Glossary: magnitude

ARM vs Thumb performance on iPhone 3GS, non floating point code

http://stackoverflow.com/questions/1198176/arm-vs-thumb-performance-on-iphone-3gs-non-floating-point-code

do optimize with gcc you would have 8 combinations to test with llvm the number of experiments is almost an order of magnitude higher. More than you can really run hundreds to thousands. For the one test I was running NOT opimizing on the C to bytecode..

Detecting Acceleration in a car (iPhone Accelerometer)

http://stackoverflow.com/questions/2733249/detecting-acceleration-in-a-car-iphone-accelerometer

a force is received project it onto said plane to get rid of sideways force etc. 5 Then use that force the known magnitude of gravity and the known direction of forward motion to essentially solve a triangle to get the forward vector. The problem.. look as they should. The difficult part is actually the detection of the forward vector. I am selecting vectors whose magnitude exceeds gravity and from there averaging them and subtracting gravity. I am doing some error checking to make sure that..

Determining the magnitude of a certain frequency on the iPhone

http://stackoverflow.com/questions/2921674/determining-the-magnitude-of-a-certain-frequency-on-the-iphone

the magnitude of a certain frequency on the iPhone I'm wondering what's the easiest best way to determine the magnitude of a given frequency.. the magnitude of a certain frequency on the iPhone I'm wondering what's the easiest best way to determine the magnitude of a given frequency in a sound. It's my understanding that a FFT function will return the magnitudes of all frequencies.. to determine the magnitude of a given frequency in a sound. It's my understanding that a FFT function will return the magnitudes of all frequencies in a signal. I'm wondering if there is any shortcut I could use if I'm only concerned about a specific..

NSString stringWithFormat swizzled to allow missing format numbered args

http://stackoverflow.com/questions/2946649/nsstring-stringwithformat-swizzled-to-allow-missing-format-numbered-args

Table View scroll when text field begin editing iphone

http://stackoverflow.com/questions/3029399/table-view-scroll-when-text-field-begin-editing-iphone

share improve this question You want to use the setContentOffset method of the table view. Determine the magnitude of the vertical scroll in pixels and then CGFloat verticalScroll ... your code here ... self.tableView setContentOffset..

Using the apple FFT and accelerate Framework

http://stackoverflow.com/questions/3398753/using-the-apple-fft-and-accelerate-framework

always have complex component 0 so A 0 .realp is used to store Bin 0 and A 0 .imagp is used to store Bin n 2 And the magnitude of each complex number is the amount of energy vibrating around that frequency. So as you can see it wouldn't be a very..

Fast, very lightweight algorithm for camera motion detection?

http://stackoverflow.com/questions/4393841/fast-very-lightweight-algorithm-for-camera-motion-detection

is is there another optical flow algorithm that's faster than Lucas Kanade if I just want to detect the overall magnitude of camera movement I don't need to track individual objects I don't even need to know which direction the camera is moving..

iPhone FFT with Accelerate framework vDSP

http://stackoverflow.com/questions/6358764/iphone-fft-with-accelerate-framework-vdsp

your audio sample data into the real part of the input and zero the imaginary part. If you are just interested in the magnitude of each bin in the frequency domain then you calculate sqrt re re im im for each output bin. If you're only interested in.. in the frequency domain then you calculate sqrt re re im im for each output bin. If you're only interested in relative magnitude then you can drop the sqrt and just calculate the squared magnitude re re im im . You would look at the magnitudes of the.. output bin. If you're only interested in relative magnitude then you can drop the sqrt and just calculate the squared magnitude re re im im . You would look at the magnitudes of the bin or bins see 2 that correspond to your frequency or frequencies..

Why is Geolocation in Mobile Safari way less accurate than the location in a native App?

http://stackoverflow.com/questions/6790368/why-is-geolocation-in-mobile-safari-way-less-accurate-than-the-location-in-a-nat

turned off on android 2.2 iOS4 and iOS5. On both android browser and iOS 4 Safari I'm getting GPS accuracy level in magnitude of 1000 meters. But on iOS 5 Safari I'm able to get down to 5 meter accuracy. Seems GPS has improved on iOS 5 but it is..

FFT on iPhone to ignore background noise and find lower pitches

http://stackoverflow.com/questions/7181630/fft-on-iphone-to-ignore-background-noise-and-find-lower-pitches

processing fft pitch tracking accelerate framework share improve this question Pitch is not the same as peak magnitude frequency bin which is what the FFT in the Accelerate framework might give you directly . So any peak frequency detector..