Thanks: https://issues.apache.org/jira/browse/MATH-574
Ben Nasatyr RBS Global Banking & Markets Office: +44 20 7085 2371 -----Original Message----- From: Gilles Sadowski [mailto:[email protected]] Sent: 12 May 2011 16:02 To: [email protected] Subject: Re: [math] Do the two vectors in RealVector.outerProduct really have to be the same size? Hello. > > thanks in advance for your time and apologies if this has been raised > before (I searched and couldn't find it). > > I recently wrote something like > > RealMatrix M = x.outerProduct(y); > > and found it throwing an exception and failing one of my tests because x and > y were different sizes. Fair enough in one sense as this is the documented > behaviour but not what one expects mathematically (see e.g. > http://en.wikipedia.org/wiki/Outer_product). > > To deal with this I found myself writing the following (extremely ugly) > code: > > RealMatrix M = (x.getDimension() == y.getDimension()) ? > > x.outerProduct(y) : > > (new Array2DRowRealMatrix(x.getData())).multiply(new > Array2DRowRealMatrix(y.getData()).transpose()); > > So I have a few questions: > > * > Can the restriction that the two vectors in RealVector.outerProduct have to > be the same size be removed? If so, should I enter a bug report or feature > request? Yes, please. > [...] Thank you, Gilles --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected] *********************************************************************************** The Royal Bank of Scotland plc. Registered in Scotland No 90312. Registered Office: 36 St Andrew Square, Edinburgh EH2 2YB. Authorised and regulated by the Financial Services Authority. The Royal Bank of Scotland N.V. is authorised and regulated by the De Nederlandsche Bank and has its seat at Amsterdam, the Netherlands, and is registered in the Commercial Register under number 33002587. Registered Office: Gustav Mahlerlaan 10, Amsterdam, The Netherlands. The Royal Bank of Scotland N.V. and The Royal Bank of Scotland plc are authorised to act as agent for each other in certain jurisdictions. This e-mail message is confidential and for use by the addressee only. If the message is received by anyone other than the addressee, please return the message to the sender by replying to it and then delete the message from your computer. Internet e-mails are not necessarily secure. The Royal Bank of Scotland plc and The Royal Bank of Scotland N.V. including its affiliates ("RBS group") does not accept responsibility for changes made to this message after it was sent. For the protection of RBS group and its clients and customers, and in compliance with regulatory requirements, the contents of both incoming and outgoing e-mail communications, which could include proprietary information and Non-Public Personal Information, may be read by authorised persons within RBS group other than the intended recipient(s). Whilst all reasonable care has been taken to avoid the transmission of viruses, it is the responsibility of the recipient to ensure that the onward transmission, opening or use of this message and any attachments will not adversely affect its systems or data. No responsibility is accepted by the RBS group in this regard and the recipient should carry out such virus and other checks as it considers appropriate. Visit our website at www.rbs.com *********************************************************************************** --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
